section 3.1: cases and form factorscptsrv.ptc.edu/localuser/wctel/4_mod3.pdf · ©2012 testout...

©2012 TestOut Corporation (Rev 11/12) LabSim PC Pro

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Section 3.1: Cases and Form Factors

The size of the system case is often determined by the motherboard form factor. The following table contains the primary motherboard types with which you should be familiar:

Form Factor

Characteristics

ATX

The ATX form factor is the most common form factor for full-sized computers.

ATX boards measure 12" x 9.6".

The CPU sits at the back top below the power supply. The power supply blows air into the case or pulls air from the case to cool the processor.

The power cable runs from the system case power switch to the system board.

The power supply can use a soft switch or soft power (the operating system can turn the computer off).

Mini-ATX

A mini-ATX motherboard is a slightly smaller variation of the full ATX size that measures 11.2" x 8.2".

The main difference between ATX and mini-ATX is the number of bus and possibly memory slots on the motherboard.

Mounting holes for both are located in the same place, making them interchangeable in most cases. A case that supports an ATX motherboard can also support a mini-ATX motherboard.

Micro-ATX

The micro-ATX form factor is an even smaller version of the ATX standard, with a maximum size of 9.6" x 9.6". Mounting holes are in the same position as ATX motherboards. The terms mini-ATX and micro-ATX are often used interchangeably, and some micro-ATX boards could be smaller than the maximum size.

Mini-ITX The mini-ITX standard is the smallest variation of the ATX standard, with a maximum motherboard size of 6.7" x 6.7". The mini-ATX standard also includes standards for a power supply that provides less than 100 Watts.

NLX

NLX is an older form factor used for slimline desktop-style computers. NLX is an improvement over an even earlier LPX form factor. NLX:

Uses a riser card in the middle of the system board (expansion slots are located on the riser card rather than the system board).

The riser card does not have built-in ports for audio, joystick, USB, network, and modem.

Supports AGP video cards.


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Includes the ability to mount the motherboard so it can slide in or out of the system case easily.

BTX

The BTX form factor was designed to give developers better options for managing system performance and balancing thermal management. With BTX:

The processor is at the front and turned on an angle to increase air flow across the processor.

A thermal module or shroud fits over the processor to move heat directly out of the system.

Many BTX cases are also ATX compatible.

Although BTX was developed as an improvement to ATX, it has not gained widespread adoption. BTX is implemented mainly by computer manufacturers such as Dell.

System cases come in the following basic types:

Type Description

Desktop

Desktop cases sit horizontally and are usually used for low-end systems that are not meant to be upgraded (i.e. there may be few or no expansion slots). Specific sizes include:

Desktop

Slim line

Tower

Tower cases can be as high as two feet tall. They have extensive room for expansion. Tower size classifications include:

Minitower typically have 1-2 drive bays for expansion

Midsize typically have between 2-4 drive bays

Full-size may have between 6-10 drive bays for expansion

Small form factor (SFF)

Small form factor computers use mini-ITX or custom motherboards to reduce the size of the system. Some SFF cases might be classified as minitowers with 1-2 drive bays. Others might include all computer components in the shape of a ball or integrated within a monitor as a single unit.

Notebook Notebook cases are generally proprietary and often vary among models.

When you purchase a system case, you will typically get the following components:

System case

Power supply (although the power supply might also be separate)


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Case fans

Plastic or rubber feet that attach to the bottom of the case

Metal screws for attaching the motherboard

Additional external connectors (such as audio, USB, and Firewire) that connect to motherboard headers

Lecture Focus Questions:

Why must the case and the power supply be matched to the motherboard?

How does the BTX form differ from the ATX form?

What is the main difference between full, mid-, and mini-tower cases?

What are the standard components typically included with a system case?


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Section 3.2: Power Supplies

You should be aware of the following facts about power supplies:

Power supplies must be matched to the motherboard and case form factor. If you have an ATX motherboard, purchase an ATX power supply. Likewise, if you have a MicroATX motherboard, purchase a MicroATX power supply.

The power supply converts AC current to DC current. o AC (alternating current) is the type of current distributed through wall sockets.

With AC, the voltage alternates (at a quick rate) between a negative and a positive charge. This type of current is good for appliances requiring a high current.

o DC (direct current) is the type of current used inside a computer. Negatively charged particles being drawn toward a positive charge create a direct current flow. This type of predictable reliable current is ideal for an application where a lower current is required.

Standard ATX Power supplies provide + 3.3 volts, +/- 5 volts, and +/- 12 volts (DC power). Most modern components require +12 volt output. MicroATX power supplies only provide + 3.3 volts and +/- 12 volts (+/- 5 volt components are not typically used in MicroATX systems.)

Each separate voltage output circuit is referred to as a rail. To avoid overloading one circuit, many newer power supplies have multiple +12 volt rails. Much like a circuit breaker in a house, separate rails allow you to distribute the power load between multiple circuits to prevent any one circuit from becoming overloaded. Each rail can power multiple devices.

Most power supplies have the capacity to receive both 110 and 220 volt power just by toggling a switch (typically red) on the power supply casing. You can use this switch when using the power supply in other countries. When troubleshooting, make sure this switch is set to the correct voltage.

o 110 volts is used in the United States. o 220 volts is used in many parts of Europe.

Many power supplies have a switch on the back that turns the power on or off.

Power supplies are rated in watts. The watt describes how much work or how much power can be supplied to various devices. The more devices you have in your computer, the more wattage you will require.

You can calculate the system's wattage requirements with the following method: o Find the wattage requirements of each individual circuit by multiplying volts by

amps (W = V x A). o Add the circuit wattage requirements together to find the total system wattage

requirement.

Power supplies include a fan that helps to cool the system. o On older ATX systems, the fan direction blows air into the case and across the

CPU. o Newer (all current) ATX systems reverse the fan direction to pull air from

inside the case (blow air out). o System case fans help improve airflow. Current ATX cases typically pull

(cooler) air in from the front, where the power supply and additional fans at the rear blow the (warmer) air out.

An ATX power supply provides soft power. This is a condition where the motherboard always has power, even when the computer is turned off. This feature enables the operating system to power off the system and enables other features such as power on for network or other events.


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The power supply includes connectors for powering various computer components. When choosing a power supply make sure it includes the necessary connectors for your motherboard. Specifically, some motherboards and processors require an extra 4-pin and/or 8-pin connector in addition to the main 20- or 24-pin power connector.

Power supply connectors are standardized following the ATX specifications. However, some computer manufacturers, such as Dell, produced power supplies with proprietary connectors. In some cases, the connectors are the same as ATX connectors, but the wiring positions might be different. When replacing a power supply, identify whether a standard ATX or a proprietary power supply is required.

You can use a power supply tester or a multimeter to test a power supply. If the +/-12 volt supply coming from the power supply drops below +/-10.8 volts or if the +/-5 volt supply drops below +/-4.5 volts, then the unit is likely failing and should be replaced.

To turn the power supply on for testing, insert a shunt on pin 16 and a ground pin (such as pin 15 or 17) on the motherboard connector.

Symptoms of bad power supply include: o The system does not start o The system shuts off o The system reboots o Fan does not run or is noisy

Never ground yourself when working on a power supply.

Use a voltmeter (multimeter) to measure the voltage on internal connectors.

Power supplies store dangerous voltages. Never open a power supply. Instead, replace the entire power supply.

The following table shows the common power supply connectors.

Connector Description

20-pin

The 20-pin connector is the main motherboard connector and supplies 3.3, 5, and 12 volts to the motherboard. On older motherboards, the CPU is powered through a 5 volt wire in this connector.

24-pin (20+4 pin)

The 24-pin motherboard connector replaces the 20-pin connector in older motherboards. The additional 4 pins supply an extra wire for 3.3, 5, and 12 volts.

Some power supplies use a 20-pin connector with an extra 4-pin connector.

Some 24-pin connectors allow you to


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disconnect 4 of the pins.

You can plug a 24-pin connector into a motherboard using a 20-pin connector (leaving the 4 extra pins unconnected).

4-pin +12 volt power (P4)

Starting with the Pentium IV processor (P4), CPUs required more power than could be provided through the main motherboard connector. In addition, processors are powered using 12 volts instead of 5 volts. The 4-pin 12 volt connector supplies 2 additional wires of 12 volt power.

Note: This 4-pin connector is not the same as the 4-pin connector used in conjunction with the 20-pin motherboard power connector.

8-pin EPS +12 volt

The 8-pin EPS connector provides 4 lines of 12 volt power.

This connector is used with some older dual processor systems or some newer quad-core processors.

Depending on the processor and the motherboard, you might be able to use a single 4-pin connector instead of the 8-pin connector (all 8 pins are typically required for quad-core processors).

Some power supplies have two 4-pin connectors (4+4) that are meant to be used together in the 8-pin connector.

6-pin PCI Express

Newer video cards require more power than can be supplied through the PCI Express bus and from the main motherboard connector. The 6-pin PCIe connector, also known as a PEG connector (PCI Express Graphics), plugs in directly to the video card to supply the additional power. The 6-pin connector provides up to 75 watts.


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Instead of a 6-pin connector, some PCI Express cards require an 8-pin connector which provides up to 150 watts. Some power supplies have a combined 6-pin and 2-pin connector (6+2).

4-pin accessory power

The 4-pin accessory power connector (often called a 4-pin Molex connector) is used by IDE hard drives, optical drives, and other accessory devices. The connector provides both 5 volts (red wire) and 12 volts (yellow wire).

Each power supply cable typically has multiple 4-pin connectors on the same cable.

When connecting devices, try to balance the devices connected to each cable.

SATA power cable

The SATA power cable has 15 pins and provides 3.3, 5, and 12 volts. As its name implies, it is used for powering SATA devices.

You can use a special adapter to convert a 4-pin Molex connector to a SATA connector.

When using an adapter, or on some power supplies, the connector only supplies 5 and 12 volts.

4-pin mini-Molex

The 4-pin mini-Molex connector provides both 5 and 12 volts and is used by floppy drives.

If your power supply does not have some of the required connectors (such as for the CPU, video card, or SATA devices), you can purchase adapters to convert from one connector to another.


How does the case form affect the type of power supply you purchase?

What function does the red switch on a power supply perform? Why is this important?

What is a watt? How does the watt rating for a power supply affect the devices you can use in a system?

What is a soft power supply?


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Why must you be careful when using a proprietary power supply?

Section 3.3: Motherboards and Buses

A motherboard, also called system board, logic board, or mainboard, is a circuit board that either houses or is connected to all of the components operating in the computer. Choosing the correct motherboard requires attention regarding which features and configurations are available. Ensure that the board chosen is compatible with the system CPU and that there are enough compatible expansion and memory slots, keeping in mind future upgrading requirements.

A typical motherboard includes the following components:

Component Function / Characteristics

Processor interface

Current motherboards have a socket that accepts the processor. Pins in the processor drop into the motherboard processor socket. The motherboard socket must match the socket type and design used by the processor (in other words, when choosing a motherboard, make sure it matches the processor you will use). Some motherboards support multiple processors and will have a socket for each processor.

Memory modules

The motherboard contains slots for different types of memory. Memory modules must be compatible with the type supported by the motherboard, the total memory capacity, and the processor and chipset support.

Expansion slots

Expansion slots allow you to add features to your computer by inserting expansion cards into the available slots. There are a number of different standard expansion slots including:

Industry Standard Architecture (ISA)

Peripheral Component Interconnect (PCI)

Accelerated Graphics Port (AGP)

Peripheral Component Interconnect Express (PCIe)

Onboard components

Many motherboards include onboard devices (such as network cards, audio cards, video cards, or USB and Firewire connections). Selecting a motherboard with onboard devices is typically cheaper than buying separate expansion cards for each feature. However, the quality of these onboard devices might not be as high as the quality you could get from devices through expansion cards.

Faceplate connectors

A faceplate fits over the motherboard's ports to secure them and protect the motherboard from dust and debris. There are standard connectors for onboard I/O components that don't require expansion cards. These connectors typically include the following:


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PS/2 mouse and keyboard ports

USB ports

Serial ports (COM 1, 2, 3, and 4)

Parallel ports (LPT 1 and 2)

Mic in, line in, line out connectors

MIDI/Game port

Onboard internal connectors

There are a number of connectors on motherboards for components such as power supplies, fans, and LED lights. System cases often have additional ports available, such as USB or Firewire ports, that need to be connected to the motherboard. These ports are connected to the motherboard's front panel connectors, which are also called headers.

External ports required by users that are not available on the motherboard are often added using expansion cards. These cards plug directly into designated expansion slots on the motherboard.

BIOS chip The BIOS chip is firmware (hardware hard-coded with software) attached to the motherboard and is essential in booting the computer.

CMOS battery The CMOS battery supplies power to the CMOS to retain system settings used by the BIOS during system boot.

Chipset

The chipset is a group of chips that facilitate communication between the processor, memory components, and peripheral devices. The chipset controls the bus speed and also power management features. Chipsets are usually attached to the motherboard and are non-upgradeable. Most modern chipsets consist of the following:

The northbridge chip provides control for main and cache memory, the front side bus, and the AGP and PCIe graphics. The northbridge is closest to the CPU. The northbridge dictates the CPU and memory type supported by the motherboard. On some motherboards, the northbridge chip includes an integrated graphic processor. The northbridge often has a heat sink and sometimes a fan, especially if it includes built-in video.

The southbridge chip provides the real time clock, controls power management, and provides the controllers for the PCI bus and USB devices.

There are two other important chipsets on a motherboard: the keyboard controller and the I/O controller.

Recent developments for the chipset include:

Combining north- and southbridge functions into a single chipset.

Moving the memory controller from the northbridge to the CPU itself to improve memory access by the CPU.


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Jumpers

Jumpers are electrical connection points that can be set to control devices and functions attached to the motherboard. Some functions controlled by jumpers are:

Clearing the CMOS password

Clearing the CMOS settings

Setting the CPU bus speed on the motherboard

Enabling or disabling onboard components

Many functions previously performed by jumpers can now be configured in the CMOS or are configured automatically.

Documentation

When selecting and working with motherboards, a good place for information is the motherboard documentation. Most motherboard documentation includes a diagram of the motherboard that identifies the components listed above and details any jumper settings. If you are missing the motherboard documentation, check the manufacturer's Web site.

When selecting a motherboard, make sure the motherboard and system case use the same form factor.

Repairing a motherboard is beyond the skill of most technicians. In most cases, it is cheaper and faster to purchase a new motherboard. You might also need to replace your motherboard to add new features or when you upgrade the processor. Use the following process to install a motherboard:

1. If you are replacing an existing motherboard, document the current BIOS settings. You might need these settings to configure the new motherboard.

2. Install the CPU, fan, heatsink, and memory before installing the motherboard in the system case. If necessary, set jumpers and DIP switches to configure devices or enable features.

3. Add riser screws (also called standoffs) to the system case to match the hole pattern on the motherboard. The standoffs prevent the motherboard circuits from touching the system case.

4. Insert the faceplate into the case. 5. Install the motherboard, securing it to the riser screws with plastic washers and screws. 6. Connect the power and accessory cables.

o Connect the main motherboard power cable and the CPU power cable. o Connect the CPU fan power cable. o Consult the motherboard documentation to identify the location for the power

switch, hard disk activity light, and other accessory cables. o Connect any case fan cables.

7. If necessary, configure voltage and clock multipliers in the CMOS. 8. Connect drives to PATA or SATA connectors. 9. Install additional devices in bus slots. 10. Connect devices (such as USB or Firewire) to motherboard header pins. 11. Document the settings of the new motherboard.

When selecting a motherboard, make sure the motherboard and system case use the same form factor.


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What factors will you consider when selecting a motherboard?

What is the difference between the northbridge and southbridge chips on a motherboard?

How can you add peripheral devices to a system?

How are PCI and PCI Express different?

What is the most common bus type for video cards on new motherboards?

Section 3.4: Processors

When selecting a CPU, be aware that you will need to match the motherboard and the CPU. Either select a CPU supported by the motherboard, or select a motherboard that will support the processor you have chosen. The following table lists several considerations for choosing a processor:

Feature Description

Manufacturer

Intel and AMD are the two producers of processors used in modern PCs.

Both Intel and AMD processors work in PC systems and support Windows software.

Intel has a larger market share, while AMD processors generally cost less.

Processor performance and special features vary between models and manufacturers.

32-bit or 64-bit

A 32-bit processor can process 32-bits of information at a time; a 64-bit processor can process 64-bits of information. Over the last several years, processors have been moving from 32-bit processors to 64-bit processors.

The biggest advantage of 64-bit processors over 32-bit processors is in the amount of memory they can use. 32-bit processors have a limit of 4GB. 64-bit processors have a theoretical limit of 16.8 TB, although operating system and current hardware limitations impose a much lower practical limit.

The operating system and applications must be written for 64-bits to take full advantage of 64-bit processing.

The processor instruction set identifies all instructions (operations) that a processor can perform.

o 32-bit processors use the IA-32 instruction set (also referred to as x86).

o Itanium processors from Intel use the IA-64 instruction set.


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o AMD64 and Intel 64 processors use the x86-64 instruction set (also referred to as x64).

32-bit applications can run on 64-bit processors using the following methods:

o Itanium processors use a software layer to translate between IA-32 and IA-64.

o x64 processors execute both 32-bit and 64-bit instructions in the hardware.

Applications typically perform better on 64-bit systems. o 64-bit applications typically perform better than 32-bit

applications. o In some cases, 32-bit applications might perform better

on 64-bit systems.

Speed

Processors operate using an internal clock that is the same as, or is a multiple of, the motherboard bus speed. The speed is represented in MHz and is also referred to as thefrequency.

You can purchase processors of the same type but with different speed ratings.

When selecting a processor, make sure the motherboard supports the processor speed by reading the motherboard documentation first.

Most motherboards automatically detect the processor speed. If not, you might need to use jumpers or edit the CMOS to configure the processor speed.

Multi-core

A multiple core processor has multiple processors within a single processor package.

Dual-core, triple-core, and quad-core processors are typical in desktop systems.

Multi-core systems enable the operating system to run multiple applications simultaneously. Without multiple processors, applications appear to run at the same time, but must wait their turn for processing time from the single processor.

Some applications can be written to execute on multiple processors at the same time.

Some motherboards use two (or more) processor sockets to provide a multiple processor solution. Multi-core processors use a single motherboard socket to support multiple processors.

Cache

Cache is memory that the processor can access directly without using the system RAM. There are three types of processor cache:

Level 1 (L1) cache is integrated on the processor die itself and stores instructions for the processor. On multi-core systems, each processor typically has its own L1 cache. Some processors might


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have two L1 caches, one for instructions and one for data.

Level 2 (L2) cache is additional cache used for both instructions and data. Depending on the processor, L2 cache might be shared between two or more cores, or exclusive to a single core.

Level 3 (L3) cache is additional cache beyond the level 2 cache. For multi-core systems, L3 cache is shared between all cores.

Be aware of the following regarding processor cache:

The size of the cache increases as you move from L1 to L3, with L1 cache being the smallest.

As a general rule, a processor with more cache performs better than a processor with less cache (all other things being equal).

Originally, only L1 cache was on the processor die, with L2 cache being on the motherboard between the CPU and the RAM. As processor technology has advanced, L2 cache moved to the processor die, with L3 cache being on the motherboard. Today, all three cache levels are located on the processor.

Process size

The process size refers to the manufacturing process used to etch transistors onto the silicon wafer that will become the CPU. A smaller process size means smaller transistors, which translates into a smaller CPU die with more transistors and less power consumption. Process size is expressed in microns (such as .25 microns) or nanometers (90 nm which equals .09 microns).

Hyper-threading

Hyper-threading is a feature of some Intel processors that allows a single processor to run threads (instructions) in parallel, as opposed to processing threads linearly. Hyper-threading enables a processor to execute two threads at the same time. For example, on a quad-core Intel system that supports hyper-threading, the processor can execute 8 threads at a time (2 on each core).

Hyper-threading is not the same as multithreading. Multithreading is a feature of an application that allows it to send multiple threads at the same time. Applications are typically written to support multithreading to take advantage of multiple cores (executing threads on two or more processors at the same time) or hyper-threading features.

Throttling

Throttling is the process of modifying the operating characteristics of a processor based on current conditions.

Throttling is often used in mobile processors to change the operating frequency to minimize power consumption and heat output.

Throttling can also be used in low memory conditions to slow down the processing of I/O memory requests, processing one sequence at a time in the order the request was received.

Related to throttling, processors or the operating system can shut down unused cores in multi-core systems to conserve energy.


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Some Intel processors include a Turbo Boost feature. Turbo Boost, the opposite of throttling, allows the processor to dynamically run above its rated speed to improve performance.

Mobile processors

Mobile CPUs are used in notebook computers where portability and mobility are a concern. Special versions of processors are built to minimize power consumption and the amount of heat generated.

Virtualization

Virtualization allows a single physical machine (known as the host operating system) to run multiple virtual machines (known as the guest operating systems). The virtual machines appear to be self-contained and separate physical systems.

Virtualization is performed by adding a layer between the physical system and the operating system. This layer acts as the hardware to the guest system.

Early virtualization was performed using software only. Newer virtualization uses special instructions supported by the processor to improve performance.

VMware is the most popular virtualization solution. Microsoft has several virtualization products including Virtual PC, Virtual Server, and Hyper-V.

If you are planning on implementing a virtual solution, check to see whether hardware support in the CPU is required. Hardware support is provided by processors with the following features:

o Intel's Virtualization Technology (VT) o AMD's AMD Virtualization (AMD-V)

Integrated memory controller

In a traditional processor design, the processor is connected to the front side bus and the Northbridge chip. The processor communicates with other system components through the front side bus. Smaller manufacturing size has reduced the overall size of a processor, leaving more room on the processor die for additional cores or cache. To improve performance, some processors include the memory controller on the processor die rather than in the Northbridge chip, resulting in faster memory access by the processor.

Cooling

Processors require some form of heat dissipation system to function properly. Without a heat dissipation system, a processor will overheat and burn out in less than a minute. Most modern CPUs require a heat sink and a fan. Between the CPU and the heat sink, thermal paste or a thermal pad helps in the transfer of heat from the CPU to the cooling unit.

For a long time, processor clock speed was used as a measure of processor performance. This is not necessarily true for newer processors for the following reasons:

If two processors are of the same type, higher speed typically means higher performance. With processors of different types, speeds might not be comparable.

It is important to make sure your mother board can support the speed of your processor.


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Many processors use a performance rating instead of speed with a higher number indicating a better-performing processor. However, performance ratings are typically only applicable between models of the same manufacturer.

In some cases, buying a processor with double the cache can nearly double the performance.

Dual core processors offer better performance, but typically not double. Software must be specially written to take best advantage of the dual core processors.

Special instruction sets supported by a processor can increase performance. For example, hyperthreading support on Intel processors can boost performance for specific types of operations.

Performance can also be increased by modifying other system components such as adding more RAM, using a faster disk, or improving cooling and ventilation.

Overclocking is a feature that causes the processor to operate at a higher speed. Overclocking is typically performed by those who want to get the maximum performance from their systems. Some important things to know about overclocking are:

o Overclocking can cause system instability, component damage, and can void your warranty.

o Motherboard bus, processor, and memory settings should be adjusted to match.

o Overclocking may require more voltage. o Overclocking often increases heat output. For this reason, it may be necessary

to upgrade your cooling devices.

When choosing a motherboard, you need to ensure that the board is compatible with the system CPU that you intend to use.

Your motherboard has a socket that accepts the processor. The motherboard socket must match the socket type and design used by the processor (in other words, when choosing a motherboard, make sure it matches the processor you will use). Some motherboards support multiple processors and will have a socket for each one.

Processor sockets can be categorized according to how the processor makes contact with the leads in the processor socket:

Pin Grid Array (PGA): PGA processors implement a series of pins on the underside of the processor package in an array. The pins are inserted into corresponding receptacles within the processor socket on the motherboard.

Land Grid Array (LGA): The LGA socket moves the connecting pins from the processor package to the socket itself. Conducting pads are implemented on the bottom of the processor that contact the protruding pins from the processor socket.

Some commonly-implemented processor sockets include the following:

Intel: o 775: Used with the Intel Pentium 4, Celeron D, Intel Pentium 4 Extreme Edition,

Pentium D, Pentium Dual-Core, Core 2 Duo, Core 2 Extreme, Core 2 Quad, Xeon, and Celeron processors.

o 1155: Used with the Intel Pentium 4, Celeron, Core i3, Core i5, Core i7, Core i7 Extreme, and Xeon processors.

o 1156: Used with the Intel Pentium 4, Celeron, Core i3, Core i5, Core i7, and Xeon processors.

o 1366: Used with the Intel Celeron, Core i7, and Xeon processors.

AMD: o 940: Used with the AMD Opteron and Athlon 64 FX processors.


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o AM2: Used with the AMD Athlon 64, Athlon 64 X2, Athlon 64 FX, Opteron, Sempron, and Phenom processors.

o AM2+: Used with the AMD Athlon 64, Athlon 64 X2, Athlon II, Opteron, Phenom, and Phenom II processors.

o AM3: Used with the AMD Phenom II, Athlon II, Sempron, and Opteron processors.

o AM3+: Used with the AMD Phenom II, Athlon II, Sempron, and Opteron processors.

o FM1: Used with the AMD Athlon II processor along with the A-series APUs. o F: Used with the AMD Opteron and Athlon 64 FX processors.

Remember the following when installing a CPU:

The CPU and motherboard socket type must match. The socket identifies the number and layout of pins.

In addition to the socket type, the motherboard must support the processor speed.

For newer processors released after the motherboard, you might be able to add support for the processor by updating the BIOS.

o Typically, the processor will run at a speed lower than its rating if the motherboard does not support the higher speed.

o As a best practice, you should update the BIOS shortly after installing the processor (you must have a processor and memory installed to update the BIOS).

The process size refers to the manufacturing process used to etch transistors onto the silicon wafer that will become the CPU. In general, the smaller the process size, the less power required by the CPU. Mobile processors are designed to use less power.

Use anti-static protection when installing a CPU.

A Zero Insertion Force (ZIF) socket uses a lever to allow installation of the processor. Drop the processor into place, then push down on the lever to lock the processor into place.

When installing a CPU, be sure to orient the CPU appropriately with the socket. o In most cases, the pin array is keyed so that the CPU can be inserted in only

one way. o For processors that can be inserted multiple ways, be sure to line up pin 1 on

the processor with pin 1 in the processor slot. Pin 1 is typically identified with a dot or a triangle.

When installing a processor in a multi-processor system, unused processor slots must be filled with a special terminating resistor.

When adding multiple processors in a multi-processor system, be sure that the speed of the processors are the same.

CPUs require a heatsink, and most desktop systems also use a fan for cooling.

When installing a heat sink, use thermal grease or a thermal pad between the processor die and the heat sink. This maximizes heat transfer between the processor and the CPU.

When the CPU includes a fan, be sure to connect the fan power to the motherboard.

Most motherboards automatically detect the processor speed. If not, you might need to use jumpers or edit the CMOS to configure the processor speed.

Most newer processors are 64-bit processors that can run both 32-bit and 64-bit applications.

o The biggest advantage of 64-bit processors over 32-bit processors is in the amount of memory they can use. 32-bit processors have a limit of 4GB. 64-bit processors have a theoretical limit of 16.8 TB, although operating system and current hardware limitations impose a much lower practical limit.

o The operating system and applications must be written for 64-bits to take full advantage of 64-bit processing.


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o You will need to install a 64-bit operating system to take advantage of the 64-bit abilities of the processor (and the higher memory available). You can, however, install a 32-bit operating system on a computer with a 64-bit processor.

Unlocked processors are processors whose speed can be changed above their rated speed through overclocking.

o With overclocking, you increase the speed and often the voltage to increase the performance of the processor.

o Overclocking typically voids the CPU warranty and could lead to shorter component lifetimes.

o Some multi-core processors (such as a triple core CPU) have additional cores that have been disabled. With the appropriate motherboard support, you might be able to unlock and use the additional core(s). However, stability of the extra cores is not guaranteed.


What is the difference between the three levels of cache memory?

What is the biggest limitation of using a 32-bit processor?

What factors should be considered when comparing the speed of computers?

What are the benefits of using a smaller process size during CPU manufacture?

What is the difference between hyper-threading and multithreading?

Under what circumstances might you choose to use throttling?

What is virtualization? Which CPU features enable advanced virtualization support?

What three components are used with a CPU to dissipate heat?

Section 3.5: Memory

Random Access Memory (RAM) can be classified as one of two types:

Type Description

Dynamic RAM

(DRAM)

Dynamic RAM stores data using a single transistor for every bit of data (a 0 or a 1). To maintain the state of the transistor, dynamic RAM must continually supply power to the transistor; when the power is turned off, the data is lost.

DRAM is simple to implement.

DRAM can have a very high density (i.e. high storage capacity).

Because of the simplicity, DRAM is relatively inexpensive.

DRAM is used in the main system memory on a computer.


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Static RAM (SRAM)

Static RAM stores data using four transistors for every bit of data. Static RAM does not require constant power to maintain the contents of memory.

SRAM is more complex and less dense (i.e. lower storage capacity) than DRAM.

SRAM is faster and requires less power than DRAM.

Regular SRAM still requires periodic power to maintain the state of memory, but the rate of refresh is less than with DRAM. Non-volatile SRAM (nvSRAM) is able to maintain memory contents when the power is turned off.

SRAM is typically used in cache memory, such as CPU cache, hard disk cache, and cache in networking devices.

All system memory used in personal computers is dynamic RAM. Individual DRAM chips are packaged onto a board that contains circuitry for reading and writing to the memory. You should be aware of the following standards for RAM:

Standard Description

SDRAM (Synchronous Dynamic RAM)

SDRAM is synchronized with the system bus clock, allowing it to receive instructions in a continuous flow. New instructions can be received, even before the first instruction has finished executing.

SDRAM accepts one command and one data set per clock cycle. For this reason, SDRAM is sometimes called single data rate synchronous DRAM (SDR SDRAM).

SDRAM can read or write 64-bits at a time, matching the width of the system bus. (The set of data transmitted together is called a word.)

A 64-bit word is stored across 8 DRAM chips, with each chip receiving 8-bits of data.

SDRAM operates at 3.3 volts (original SDRAM operated at 5 volts) at bus frequencies between 33-166 MHz.

DDR (Double-Data Rate Synchronous

Dynamic RAM)

DDR is a variation of the original SDRAM.

All variations of DDR are synchronized with the system clock and accept 64-bit words.

DDR accepts a single command and two consecutive data sets per bus clock cycle (double the data within the same time period).

Operating at the same frequency, DDR has twice the bandwidth of SDRAM.

DDR operates at 2.5 volts at bus frequencies between 100-200 MHz.


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DDR2

DDR2 doubles the data transfer rate of DDR, for four times the bandwidth of SDRAM.

DDR2 accepts four consecutive 64-bit words per bus clock cycle.

DDR2 includes a buffer between the data bus and the memory.

DDR2 operates at 1.8 volts at bus frequencies between 200-533 MHz. The internal memory frequency is half that of the bus frequency (100-266 MHz).

DDR3

DDR3 doubles the data transfer rate of DDR2, for eight times the bandwidth of SDRAM (twice that of DDR2).

DDR3 accepts eight consecutive 64-bit words per bus clock cycle.

DDR3 operates at 1.5 volts at bus frequencies between 400-1000 MHz. The internal memory frequency is one-fourth that of the bus frequency (100-250 MHz).

RDRAM (Rambus DRAM)

RDRAM is an alternative to DDR that was developed jointly with Intel.

RDRAM transfers data either 16- or 32-bits at a time.

RDRAM transfers two consecutive words in a single clock cycle.

RDRAM uses a memory controller on each memory chip instead of on the motherboard or CPU. Data must pass from one memory module to the next in line.

Continuity modules must be installed in unused memory slots.

RDRAM operates at 2.4 volts at 400-800 MHz. Because of the higher frequencies, RDRAM modules always have heat spreaders to dissipate heat.

SDRAM, DDR, and RDRAM are no longer used in modern motherboards, although you might encounter these types of memory in older systems. DDR3 will eventually replace DDR2, and will be eventually replaced by DDR4 or DDR5.

DDR increases the memory bandwidth by doubling the amount of data sent within a single clock cycle. Another method for increasing memory bandwidth is by providing multiple channels within the memory controller.

Dual-channel systems use two memory controllers, while triple-channel systems use three memory controllers. Each memory controller can communicate with one or more memory modules at the same time.

To operate in dual-channel mode, install memory in pairs; to operate in triple-channel mode, install memory in sets of three.


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Dual-channel systems theoretically double the bandwidth. However, in practice, only a 5-15% increase is gained.

Dual-channel and triple channel support is mainly a function of the motherboard (i.e. the memory controller), not the memory itself. DDR, DDR2, and DDR3 can all work in dual-channel systems (depending on the memory supported by the motherboard); a triple channel system can only use DDR3.

The memory controller is in the Northbridge chip on the motherboard. Newer processors move the memory controller onto the processor chip, allowing the processor to communicate with RAM without going through the front-side bus.

Memory comes in various form factors (or packages), with the form factor determining the number of pins and the size of the memory module. Generic form factor labels that you should be familiar with are:

Form Description

SIMM

A SIMM (single in-line memory module) has pins on both sides of the module, but the pins are redundant on both sides.

SIMMs were used with older memory modules (not SDRAM or DDR).

SIMMs had a 32-bit data path, so you had to install them in pairs for a 64-bit bus.

DIMM

A DIMM (dual in-line memory module) has pins on both sides of the module, with each pin being unique.

DIMMs have a 64-bit data path that matches the system bus width.

RDRAM and DDR/2/3 are packaged into DIMMs, with each specification having a unique number of pins and notch position.

SO-DIMM

A SO-DIMM (small outline dual in-line memory module) is a smaller DIMM used in laptops. RDRAM and DDR/2/3 are packaged into DIMMs, with each specification having a unique number of pins and notch position.

RIMM

A RIMM (Rambus in-line memory module) is a memory module used by the RDRAM specifications.

A single channel RIMM has a 16-bit data path.

A dual channel RIMM has a 32-bit data path.

The best way to ensure you get the correct RAM for your system is to consult the motherboard documentation. In addition, there are several Web sites on the Internet where you can look up your system or scan your system to find the correct memory type to install. When selecting RAM, you will need to consider the following factors:


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Characteristic Description

Packaging (form)

When you are purchasing RAM for a system, the most important consideration is the packaging (or form). The packaging controls both the physical size of the memory module as well as the memory standard (DDR, DDR2, etc.). If you purchase the wrong type of RAM, it most likely will not fit. If it does, it might have different voltage requirements than what is supported by your motherboard.

Capacity

The capacity (sometimes called the size) refers to the storage capacity of the memory module (i.e. 256 MB, 512 MB, 1 GB). The total capacity of memory that you can install in your system is limited by:

The number of memory slots on the motherboard.

The maximum total capacity that can be installed. For example, most systems will have a maximum of between 3 and 12 GB of RAM.

The maximum module capacity. For example, the motherboard might only be able to accept up to 2 GB or 4 GB modules.

For example, if your motherboard had a total of three slots, with a maximum module size of 1 GB and a system maximum of 3 GB, if you had two 512 MB modules installed, you would only be able to add a single 1 GB module bringing the total up to 2 GB. You could also replace one or both of the 512 MB modules bringing the total to 2.5 or 3 GB respectively.

Frequency

For optimal performance, you should match the memory frequency (sometimes called the speed) with the frequency supported by the system bus/memory controller.

The motherboard front side bus restricts the maximum frequency.

Memory frequency is equal to or is a multiplier of the front side bus.

You can install slower memory in the motherboard, but this will degrade performance.

You can install faster memory in the motherboard, but it will only operate up to the maximum supported by the motherboard.

Most memory modules include an SPD (Serial Presence Detect) chip that identifies its frequency. The BIOS uses the information in this chip to set the frequency automatically.

On many systems, you can edit the BIOS manually to change the frequency.

When you mix memory with different frequencies, all memory will operate at the lowest frequency.

The following link describes ratings that describe the frequency and bandwidth capabilities of memory. Memory Ratings

http://content.testout.com/pcpro2012/Resources/CompTIA/PCPro2012/mem_char/mem_speed.htm


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CAS latency/timing

Another factor that affects the performance of memory is the latency associated with accessing data in RAM.

With a read request, there is a delay between the time the data is requested and the time that the data is available on the module's output pins. This delay is called the CAS latency (CL).

Older memory expressed the delay in nanoseconds, but DRAM uses a ratio based on the clock frequency to describe the delay.

For memory modules of the same type and frequency, a lower CL number indicates less delay (i.e. "faster" RAM).

Because CL is related to the frequency, you cannot directly compare the CL between modules with a different frequency. For example, a DDR2 module operating at 533 MHz with a CL of 6 has more delay than a DDR3 module at 667 MHz with a CL of 7.

In addition to CAS latency, there are other memory characteristics that describe the delay for performing other types of operations. Collectively these values are referred to as the memory timings.

For stable operations, the bus must take into account these latencies to keep the bus and the memory synchronized.

Manufacturers test memory modules and rate them based on the operating frequency and the timing characteristics. Settings that produce stable performance are then encoded into the SPD module on the memory. The BIOS then reads this information to know how to configure memory settings on the motherboard.

For many systems, you can manually modify the memory timings and frequency. Running RAM at a lower clock speed enables you to decrease the CAS latency setting; increasing the frequency must usually be compensated for by increasing the CL (and other) settings.

Error correction

Some memory modules include error correction on the module itself. Two different approaches to error correction are used:

With parity, a 1 or a 0 is appended to each byte so that the total number of 1s is always either even or odd. Parity methods can detect errors in only one bit, but cannot fix them because they cannot determine the specific bit with the error. The parity error checking method is older and has almost been completely eclipsed by the new ECC method.

Using Error Correcting Code (ECC), a value is appended to the end of each byte so that the value of the data can be compared and recalculated if an error occurs. Error Correcting Code is an improvement on parity techniques because errors in more than one bit can be detected and corrected.

You might hear the terms parity and ECC being used interchangeably. Modern systems simply use ECC for error detection and correction.


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Keep in mind the following facts about error correcting memory:

Memory modules with ECC have extra memory chips on the module (typically 9 modules instead of 8). If the number of chips is divisible by 3 or 5, the module is likely ECC memory.

ECC or parity memory must be supported by the motherboard.

Because it is more expensive, ECC memory is typically used only in servers.

ECC memory is slower than non-ECC memory.

Do not mix ECC and non-ECC memory in a system.

Buffered (registered)

Buffered (or registered) RAM has a buffer that holds memory addresses or data before it is transferred to the memory controller.

Buffered RAM improves stability on systems with a lot of RAM (over 1 GB).

Buffered RAM might slow system performance.

ECC modules are typically buffered.

Buffered RAM must be supported by the motherboard.

Some motherboards require buffered memory.

Single- or double-sided

Single-sided RAM has memory modules that are organized into a single logical bank; double-sided RAM has modules organized into two banks.

The computer can only access data in one bank at a time. Therefore, single-sided RAM allows access to all of the memory, while with double-sided RAM, the computer must switch between banks.

Originally, double-sided RAM had modules on both sides of the circuit board, and single-sided RAM had modules on only one side. However, you can also have double-sided RAM with modules on only one side, where internally the memory is divided into separate banks.

Single-sided memory of the same capacity as double-sided memory uses half the number of memory modules (modules are denser, with a higher individual capacity).

Some older motherboards are unable to use double-sided memory, while some that allow double-sided memory can only use up to half the total memory when all memory slots are filled, or mixing single- and double-sided together might not be allowed.

The following table compares the different types of memory.

All graphics are at 3/4 size.


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Package

SDRAM (Synchronous Dynamic RAM) DIMM

Notice the notch in the middle and the notch to the far left. SDRAM memory has 168 pins.

RDRAM (Rambus DRAM) RIMM

Notice the two notches in the middle, one in the center and one off to one side. RDRAM has 184 pins.

DDR (Double-Data Rate Synchronous Dynamic RAM) DIMM

DDR memory has a single notch, slightly off center. DDR memory has 184 pins.

DDR-2 DIMM

DDR-2 memory differs from DDR memory as follows:

The notch is slightly closer to the middle.

It has more pins (240) than DDR memory. While you don't need to count the pins, you should notice that the pins are smaller because they have to fit in the same space as the DDR memory.


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DDR-3 DIMM

DDR-3 memory has a single notch off to one side, more off-center than the notch for DDR or DDR-2. Like DDR-2, DDR-3 has 240 pins.

144-pin SODIMM

SODIMMs are much smaller than other memory, perfect for notebook computers. Notice the notch slightly off center. 144-pin SODIMMs are used by SDRAM, DDR, and DDR-2 memory.

200-pin SODIMM

Notice the notch farther off center than the 144-pin SODIMM. You might also be able to notice the higher pin density. 200-pin SODIMMs are used by DDR-2 and DDR-3 memory.

Be aware of the following when selecting memory to install in your system.

The best way to get compatible memory is to check the motherboard compatibility information, read the motherboard documentation, or use an online tool that scans your computer for compatible memory modules.

Memory packaging and capacity must match what is supported by the motherboard.

You can add single memory modules to computers that use SDRAM and DDR (including 2 and 3). Most computers that use Rambus memory require that you add modules in pairs.

The total capacity of memory that you can install in your system is limited by: o The number of memory slots on the motherboard. o The maximum total capacity that can be installed. For example, most systems

will have a maximum of between 3 and 16 GB of RAM. o The maximum module capacity. For example, the motherboard might only be

able to accept up to 2 GB or 4 GB modules.


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o The maximum amount of memory that can be addressed (used) by the operating system. A 32-bit operating system can use between 3-4 GB of memory, while a 64-bit operating system can use more.

You can install more than 4 GB of memory in a system that uses a 32-bit operating system; however, the operating system will only be able to use between 3-4 GB of that memory.

Be aware of the following regarding the memory speed: o Most memory modules include an SPD (Serial Presence Detect) chip that

identifies its frequency. The BIOS uses the information in this chip to set the frequency automatically.

o You can install slower memory in the motherboard, but this will degrade performance. If you mix faster and slower modules, all memory will operate at the slowest module installed.

o You can install faster memory in the motherboard, but it will only operate up to the maximum supported by the motherboard.

o If the BIOS does not configure memory to run at its highest rated speed: Verify that the motherboard supports that speed. You might be able

to update the BIOS to support faster memory. The SPD on the memory is often set below the maximum rating for

the memory. To use the maximum speed settings, you might need to manually configure the speed and timing settings for the memory (if the motherboard allows you to do this).

Most desktop motherboards do not support ECC or buffered memory. Some motherboards require ECC or buffered memory.

o Memory modules with ECC have extra memory chips on the module (typically 9 modules instead of 8). If the number of chips is divisible by 3 or 5, the module is likely ECC memory.

o Do not mix ECC and non-ECC memory in a system.

Most newer motherboards support both single- and double-sided memory (referring to how memory is grouped into a single or two banks). However, verify compatibility before purchasing.

Be aware of the following when installing memory:

Memory modules are very sensitive to ESD. Be sure to take proper steps to prevent ESD.

Install memory in the correct slot. Although several memory slots might be open, some system boards require that you use specific slots. Check the system board documentation for more details.

o For many systems, start with the first bank. The first memory bank is often closest to the processor.

o On some systems you should fill each bank in order.

Align the memory before inserting, and do not force the module in place. Most memory is keyed to prevent it from being installed backwards or in incompatible slots.

Most RAM is held in place with small tabs on either end. To remove RAM from a motherboard, push the tabs down to rotate them back, then pull the RAM straight up.

For Rambus memory (RIMMs), add a continuity module in all empty RIMM slots.

For a dual (or triple) channel configuration: o Modules must be installed in matching sets (capacity and speed), preferably of

the same manufacturer and model.


27

o You can typically use different capacity modules between sets. For example, you can use two 1 GB modules as one set, and two 512 MB modules in the second set.

o Install modules in the slots specified in the motherboard documentation. Many motherboards color the slots, with slots used within a set having the same color.

If you install single memory modules, the system will continue to use the memory, but cannot use the memory in dual-channel mode.

Following installation, power on the system and check for errors. Most BIOS programs include a memory count that displays the total amount of system memory. If it does not count the proper amount of memory, you might have installed the memory incorrectly or you may have a faulty memory module. Also, if the BIOS generates an error between 200 and 299, the error is a memory error.

Most systems will configure memory settings (frequency, voltage, and timing including latency) automatically based on information in the SPD chip. If necessary, edit the BIOS to manually configure memory settings.


What is the difference between SRAM and DRAM?

What are two advantages of using DDR3 memory over DDR2 memory?

What are two places where the memory controller might be located in modern PC systems?

Why is consulting the motherboard documentation so important when purchasing memory?

You have DDR2 memory with a CAS latency of 6 and DDR3 memory with a CAS latency of 7. What can you tell about the relative speed of the two memory modules?

What is the difference between ECC and registered memory?

Section 3.6: BIOS

You should know the following facts about the BIOS and CMOS:

Component Description

Basic Input Output System (BIOS)

The BIOS is a program stored in a read-only memory (ROM) chip that the CPU automatically loads and executes when it receives power. Important things to know about the BIOS are:

The BIOS program controls the startup process and loads the operating system into memory.

The BIOS is an example of firmware.


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You should check for BIOS updates from manufacturers frequently. Updating the BIOS (called flashing the BIOS) makes new features available, such as allowing the BIOS to recognize newer hardware devices.

Most BIOS chips are 64k in size, though there is 384k address space available for the BIOS to use.

SCSI devices include a BIOS chip on the device. These devices have their own ROM chip called an option ROM.

Some motherboards have two BIOS chips, one for the main BIOS and a second for a backup.

Complementary Metal-Oxide

Semiconductor (CMOS)

CMOS memory is a special RAM chip powered and maintained by a small battery that holds basic configuration data your computer needs in order to start. Important things to know about the CMOS are:

To change the data stored in CMOS memory, use a CMOS editor program that is part of your BIOS.

The CMOS battery can be a low-voltage dry cell, lithium mounted on the motherboard, or even AA batteries in a housing clipped on a wall inside of the case. The electric current is about 1 millionth of an amp and can provide effective power for years.

If the voltage of the battery drops significantly, you may lose your CMOS settings every time you power-off or power-on your computer. If a CMOS battery fails, replace it and afterwards reenter the CMOS information.

During the computer's startup procedure, you can press one or more keys to open a CMOS editor so you can change the data stored in CMOS memory. This CMOS setup program is part of the BIOS program. The key or keys you press to open the CMOS editor depend on the BIOS manufacturer. The easiest way to find out which key to press is to read the screen as it boots or to consult the motherboard documentation. The most common keys are Delete, Insert, F1, and F2.

Common reasons for editing the CMOS settings are:

To change the boot device order.

To enable or disable motherboard devices.

To add a password to the setup program to prevent unauthorized access.

If you set a BIOS password and then forget it, you will be unable to edit CMOS settings.

To remove the password for most motherboards, move or remove a jumper, then replace it after a specific period of time. Removing the battery also works, but will remove all CMOS data, not just the BIOS password.

To configure processor or memory settings (such as when you need to set operating speeds or when you want to overclock hardware settings).


29

(In rare cases) To manually configure device properties for legacy devices.

One of the main jobs of the BIOS is to help start the system. The following process is used when you turn a computer on:

1. Power is supplied to the processor. The processor is hard-coded to look at a special memory address for code to execute.

2. This memory address contains a pointer or jump program which instructs the processor where to find the BIOS program.

3. The processor loads the BIOS program. The first BIOS process to run is the power on self-test (POST). POST does the following:

1. Verifies the integrity of the BIOS code. 2. Looks for the BIOS on the video card and loads it. This powers the video card

and results in information being shown on the monitor. 3. Looks for BIOS programs on other devices, such as hard disk controllers and

loads those. 4. Tests system devices, such as verifying the amount of memory on the system.

4. After POST tests complete, the BIOS identifies other system devices. It uses CMOS settings and information supplied by the devices themselves to identify and configure hardware devices. Plug and Play devices are allocated system resources.

5. The BIOS then searches for a boot drive using the boot order specified in the CMOS. 6. On the boot device, the BIOS searches for the master boot loader, then loads the boot

loader program. At this point, the BIOS stops controlling the system as control is passed to the boot loader program.

7. The boot loader program is configured to locate and load the operating system. 8. As the operating system loads, additional steps are taken to load all additional programs

and configure devices for use by the operating system.

From time to time, your PC's manufacturer may release updates to your BIOS firmware. To update the BIOS, you will need to download the update along with a utility provided by your PC manufacturer that is used to rewrite data stored in the BIOS chip. This process is called flashing the BIOS. The actual steps you should follow to flash the BIOS will vary by manufacturer.

You should connect your PC to a UPS before flashing the BIOS. If a power outage occurs during the flash process, it will irrecoverably damage the BIOS and prevent your system from booting.


What are the functions of the BIOS?

What is the role of CMOS? How does it differ from the BIOS?

Why does the CMOS require a battery?

What might be some common reasons for editing the CMOS settings?

What determines the keystroke to open a CMOS editor? How can you find this information?

What functions are performed in the POST process?


30

Section 3.7: Expansion Cards

Expansion slots provide a connection for a number of devices and functions. To add features to your computer, you can typically add a peripheral card to an existing bus slot. The following table lists common expansion buses in a PC system:

Slot Characteristics

Peripheral Component

Interconnect (PCI)

PCI supports a 32- or 64-bit I/O bus providing compatibility with both 486 and Pentium machines.

This bus is processor independent (the CPU and the PCI bus can process concurrently).

PCI is plug-and-play, meaning that newly installed devices can be detected and configured automatically.

PCI buses are most commonly used for devices such as sound cards, modems, network cards, and storage device controllers.

PCI slots are typically white.

The PCI bus is usually 32-bits wide, although 64-bit versions were used as well. Running at 33 MHz, it can transfer data at 133 MB/s (or 266 MB/s for 64-bit versions).

Mini-PCI

Small form factor computers, such as laptops or micro-ATX systems, might include a mini-PCI slot. Mini-PCI devices are small cards with either 100- or 124-pins. A typical use for a mini-PCI slot is to add internal cards (such as wireless cards) to laptops.

Peripheral Component Interconnect

Express (PCIe)

PCI Express (PCIe) is a next generation I/O bus architecture. Rather than a shared bus, each PCIe slot links to a switch which prioritizes and routes data through a point-to-point dedicated connection and provides a serial full-duplex method of transmission.

Basic PCIe provides one lane for transmission (x1), at a transfer rate of 250 MBps. It can also provide multiple transmission lanes (x2, x4, x8, x16, x32). Newer versions of PCIe can transfer data at an even higher rate per lane:

o Version 1: 250 MBps o Version 2: 500 MBps o Version 3: 1 GBps o Version 4: 2 GBps

In addition to greatly increased speed, PCIe offers higher quality service.

PCIe is backwards compatible and allows legacy PCI technology to be run in the same system (i.e. you can have both PCIe and PCI buses in the same system).

PCIe buses are most commonly used for video cards in


31

modern computer systems, although nearly any other device can be designed for a PCIe slot.

Accelerated Graphics Port

(AGP)

AGP is similar to PCI, but designed specifically for graphics support. Motherboards that provide AGP support have a single AGP slot. AGP is commonly used for video cards in modern computer systems, but has been replaced by PCIe. AGP slots are typically brown. Several different versions of AGP have been implemented over the years:

AGP 1.0 1x: Runs at 66 MHz with a data throughput rate of 266 MBps




Audio/Modem Riser (AMR)

A riser card is not a bus, but rather a card that attaches to the motherboard and allows inserting additional cards (called daughter cards). AMR slots typically provide sound or modem functions.

Communications Network Riser

(CNR)

CNR is a riser card slot (not a bus) that allows for inserting networking, wireless communication, sound, or modem functions.


What is an advantage of the PCIe bus over the PCI bus?

Which type of devices typically use mini-PCI cards?

Which buses are commonly used by graphics cards?

What type of slot can a PCIe x1 card be placed in?

How are cards added to an AMR slot?

Section 3.8: Video

When choosing a video card, consider the following factors:

Factor Description

Bus type Video cards must be compatible with the buses or slots on


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the motherboard. Common slot types used by video cards are:

Current video cards typically use AGP and PCI express slots.

Video cards in PCIe slots usually require 16x slots. AGP video cards use either 4x or 8x slots.

Older cards used PCI and VESA slots.

Some motherboards include a built-in video card integrated on the Northbridge chip. This video card is actually part of one of the buses on the system (PCIe, AGP, or PCI).

Monitor interface

The video card includes a connector for attaching the monitor. Choose the video card with the connector(s) you need:

A VGA monitor connects using a DB-15 connector. Video cards often list this connector as a D-sub connector.

A DVI connector connects to an LCD monitor. o Most DVI connectors are DVI-Integrated (DVI-I)

connectors that send either analog or digital signals based on the type of cable that is connected.

o Older cards might have a DVI-A (analog) or DVI-D (digital) interface.

You can use special conversion plugs if necessary to convert from VGA to DVI (or the other way around). However, you must have a special conversion box to convert from analog to digital signals.

Many videos cards include an HDMI connector for connecting to an HD TV or monitor with an HDMI port.

By purchasing a video card with dual heads (two output connectors capable of displaying video simultaneously), you can use dual monitors (as long as the operating system supports dual monitors).

Many newer video cards include one VGA connector and one DVI connector.

Processing capabilities

Video cards include a processor (called a graphics processing unit or GPU) that takes over video rendering from the CPU, thereby increasing video performance.

When selecting a video card, you have a wide choice of video processors. Different processors might improve performance or feature support.

The use of this video processor is often referred to as video hardware acceleration.

Typically, settings in the operating system control how much video processing is offloaded to the video card.

In older systems, using hardware acceleration could lead to program or system instability. Decreasing the percentage of hardware acceleration often resolved the problem.

Video cards also have a clock speed. Higher speeds typically


33

mean better performance.

Multi-GPU

For increased performance, especially in games, you can install multiple video cards and link those cards together so that multiple GPUs draw a single screen.

Scalable Link Interface (SLI) from nForce and CrossFire from ATI are two different methods for linking video cards.

Cards are linked using a special bridge clip or through software (depending on the implementation).

The motherboard and the video cards must each support the selected method (either SLI or CrossFire). The motherboard must have multiple 16x PCIe slots.

In most cases you will need to install identical video cards, or at least video cards with very similar specifications.

Memory

Video cards have built-in memory. The amount of memory on the card effects performance as well as other characteristics of the display.

The amount of memory ranges from 32 MB up to 2 GB (or more).

Onboard video cards (integrated on the motherboard) use a portion of the system memory for video processing.

Newer video cards will use the following types of memory: o DDR, DDR2, and DDR3 memory are similar to

system memory. This type of memory is cheaper and provides less performance features than using special graphics memory.

o GDDR2, GDDR3, and GDDR5 are DDR memory designed specifically for graphics.

Display quality

The quality of images and animations are determined by the following characteristics of display. The capability of your display depends on both the video card and the monitor support.

The resolution is the number of pixels displayed on screen. A higher resolution means that more information can be shown on the screen at a time. Modern standards range from 1024 (horizontal) x 756 (vertical) to 2048 x 1536 or even higher.

The color depth is the number of different colors that can be displayed on the screen at a time. Color depth is expressed in bits (a higher bit count increases the number of colors that can be displayed). Common bit depths include:

o 8-bit (256 possible colors) o 16-bit, also called high color (65,536 possible

colors) o 24-bit, also called true color (16.7 million possible


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colors) o 32-bit, also called true color (16.7 million possible

colors and alpha channel)

The refresh rate is the number of times the entire screen repaints per second. Refresh rates are measured in hertz. A refresh rate of 70 Hz or lower may cause eye fatigue. A desirable range of refresh rate is 75 Hz to 85 Hz. The refresh rate you use is dependent upon the rate supported by the card as well as the monitor.

High-bandwidth Digital Content

Protection (HDCP) support

HDCP is a method for copy-protecting digital media. The purpose of HDCP is to prevent the interception and copying of protected data streams as they are sent from a playback device (such as a DVD player) to a display device (such as an HD TV).

When playing protected content from a PC, the DVD player, video card, and monitor (or TV) must all support HDCP.

If you plan on watching protected content on your PC, or playing content from your PC to an external TV, make sure the video card supports HDCP.

TV input and output

Some video cards include features that allow them to receive video signals and output them to a TV source.

You can display the computer screen on a TV using the following methods:

o Analog TVs use an S-video port for video input. o Digital TVs use the HDMI port for input. o Many newer TVs also include a DVI input, allowing

you to connect to the DVI port on your computer. o You can also use an HDMI converter to convert a

DVI connector to an HDMI connector.

Video input allows your video card to accept a video signal from an external source, such as a DVD player or an external TV tuner box, and display it on the monitor.

A TV tuner allows your video card to accept a cable TV input and change channels from within the computer. TV tuners can process one or more of the following signals:

o NTSC, PAL, and SECAM are analog TV signal standards. NTSC was used in North America but is being phased out.

o ATSC signals are digital TV signals. When purchasing a new TV tuner, make sure it supports ATSC.

Most TV tuners use an S-video, F-type, or RCA composite port for video input.

A video capture card allows you to record the video signal that is coming into the computer from an external source. For example, you would use a video capture card to create digital copies of home movies stored on an analog tape, or a


35

TV tuner with video capture would allow you to record TV shows. A video capture card might include both video and audio inputs.

Video capture for digital sources can also be done through a FireWire connection.

HDMI audio

HDMI used in home theater systems have audio integrated with the video signal. If you connect your video card to a monitor or an HD TV using the HDMI port, only video content will be carried on the HDMI cable. Some video cards allow you to include audio with the video signal using one of the following methods:

With audio pass-through, an audio output cable is connected to the video card. The video card combines the audio signal with the video signal for HDMI output. This option is often called HDTV out.

A graphics card with an onboard audio processor can decode and process audio and send it out the HDMI port. This option is often referred to as onboard sound.

DirectX/OpenGL

DirectX is a set of Microsoft API (Application Program Interface) that improves graphic, animation and multimedia.

DirectX includes multiple components targeted to a different aspect of multimedia. For example, Direct3D is the 3D rendering component of DirectX.

Applications (typically games) are written using features included in specific DirectX versions.

To view content written to a specific DirectX version, your video card must also support that (or a higher) version.

OpenGL is an alternative standard to DirectX that is used by some applications. Video cards support both DirectX and OpenGL.

Be aware of the following when installing video cards:

Video cards must be compatible with the buses or slots on the motherboard. Common slot types used by video cards are:

o Current video cards typically use AGP and PCI express slots. o Video cards in PCIe slots usually require 16x slots. AGP video cards use

either 4x or 8x slots. o Older cards used PCI and VESA slots.

Some motherboards include a built-in video card integrated on the Northbridge chip. This video card is actually part of one of the buses on the system (PCIe, AGP, or PCI).

In addition to the bus type, select the video card based on the graphics processor type and speed, the amount and type of video memory, as well as the supported resolution and color depth.


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Video input allows your video card to accept a video signal from an external source, such as a DVD player or an external TV tuner box, and display it on the monitor.

A TV tuner allows your video card to accept a cable TV input and change channels from within the computer. TV tuners can process one or more of the following signals:

o NTSC, PAL, and SECAM are analog TV signal standards. NTSC was used in North America but is being phased out.

o ATSC signals are digital TV signals. When purchasing a new TV tuner, make sure it supports ATSC.

If you plan on watching HDCP protected content on your PC, or playing content from your PC to an external TV, make sure the video card supports HDCP.

Many newer PCI Express cards require a special 6-pin or 8-pin power connector. Be sure to connect the power after inserting the card in the system and prior to turning the system on.

If the motherboard has onboard video, disable the onboard video in the BIOS when installing a card in the bus slot.

For increased performance, especially in games, you can install multiple video cards and link those cards together so that multiple GPUs draw a single screen.

o Scalable Link Interface (SLI) from nForce and CrossFire from ATI are two different methods for linking video cards.

o Cards are linked using a special bridge clip or through software (depending on the implementation).

o The motherboard and the video cards must each support the selected method (either SLI or CrossFire). The motherboard must have multiple 16x PCIe slots.

o In most cases you will need to install identical video cards, or at least video cards with very similar specifications.

o In some cases, you can link the onboard graphic controller with a video card installed in a single PCIe slot.

o Connect the monitor to an output port on the first video card.

After installing the card, boot the system and install the driver for the card.


How does the video card affect the quality of the image on the monitor?

Which type of DVI connector can be used to send either analog or digital signals?

How does the GPU increase the video performance?

What advantages are provided by SLI and CrossFire?

What is the general function of HDCP? When should you be concerned with an HDCP video card or monitor?

What is the difference between ATSC and NTSC? Which format would you most likely choose if you wanted to watch broadcast TV in the United States?


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Section 3.9: Audio

A sound card is an expansion card (or a component of the motherboard) that manages sound input and output. Because computers use digital data, sound cards must convert analog sound into digital data, and digital data into analog sound. The following components are used to do this:

The Analog to Digital Converter (ADC) converts analog sound into digital data.

The Digital Signal Processor (DSP) is an on-board processor that reduces the CPU load.

The Digital to Analog Converter (DAC) converts digital data into analog sound (in preparation to be played on speakers).

When purchasing a sound card, be aware of the following considerations:

Component Description

Bus support Many newer motherboards have a built-in sound chipset. You can also add audio through an expansion card in a bus (such as PCI or PCIe).

Channels

Sound is split into multiple channels, which can increase the sound quality, making it more realistic. Some standard channel configurations are as follows:

2 channel audio is stereo. Examples of 2 channel audio include standard TV and radio.

4 channel audio is quadraphonic audio, an early attempt at surround sound.

6 channel, also known as DTS (Digital Theater System).

5.1 channel audio, also known as surround sound, has 5 audio channels (delivered on 5 strategically placed speakers) and 1 effects channel (delivered via a subwoofer). The commercial name for this technology is Dolby digital.

7.1 channel has 7 audio channels (delivered on 7 strategically placed speakers) and 1 effects channel (delivered via a subwoofer). This is the first technology providing error correction. The commercial name for this technology is SDDS (Sony Dynamic Digital Sound).

Sampling rate

The sampling rate is the number of analog signal samples taken over a period of time. Sample rates are expressed in cycles per second, called hertz (1,000 hertz (Hz) = 1 kilohertz (kHz)). A high sampling rate gives a more accurate representation of the sound. Examples of different sampling rates include:

8 kHz (telephone) A sampling rate of 8 kHz is adequate for conversation because the human voice's full range is about 4 kHz.

22 kHz (radio quality)

44 kHz (CD quality) This sample rate can accurately reproduce the


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audio frequencies up to 20,500 hertz, covering the full range of human hearing.

48 kHz (Digital TV, DVD movies)

96 kHz (DVD audio)

192 kHz, used by: o LPCM (Linear Pulse Code Modulation), a DVD-music

production format. o BD-ROM (Blu-ray Disc-ROM) and HD-DVD (High-

Density-DVD), two competing next-generation optical disc formats providing HD video and high density data storage.

Higher sample rates require more bits of data. For example:

8-bit sound cards use a sampling size of 256.

16-bit sound cards use a sampling size of 65,536.

20-bit sound cards use a sampling size of 1,048,576.

24-bit sound cards use a sampling size of 16,777,216.

32-bit sound cards use a sampling size of 4,294,967,296.

The bit portion of a sound card's sampling size does not correspond with the bus size.

Feature support

Additional features on sound cards provide higher quality or added functions. Some typical sound card features are listed below:

DirectSound 3D allows a computer to play audio in surround sound.

EAX is a high definition sound technology originally developed for video games. This technology provides such realistic nuances that audio can actually cue gamers.

THX is a sound quality standard, originally created for film, now available on sound cards. This is a sound card feature that allows computers to present theater quality sound output.

Dolby Digital is a technology that broadcasts sound at a frequency the human ear can hear and diminishes collateral sound. This is a sound card feature that allows computers to present higher quality sound output.

DTS (Digital Theater Systems) Digital requires an optical reader to decode physical data and send it to a computer for processing. This is a sound card feature that allows computers to present theater quality sound output.

MIDI (Musical Instrument Digital Interface) is a protocol for recording and playing audio created on digital synthesizers. This feature allows the computer to become an integrated component to a musical instrument.

Analog input and output

Analog output jacks allow you to play sound on your computer on external devices:

The speaker out connector sends signal to external speakers. This


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signal is amplified and the computer controls the sound level that is sent.

The line out connectors send audio to other sound devices. This signal is unamplified.

Analog input jacks allow you to record audio through the sound card.

The line-level (line in) connector receives signals from CD players and musical instruments coming from the line-out port of the other device.

The mic-level (microphone in) connector receives signals from microphones.

Digital audio

Most audio devices, such as stereo consoles, TVs, and speakers require analog audio. Newer devices, such as some CD players, DVD players, and HDTVs, are capable of processing digital audio signals. Digital audio support in a sound card:

Allows you to play digital audio directly from an internal CD player.

Allows for compression of audio data to support Dolby Digital or DTS surround sound.

Can use fiber optic cables to eliminate electrical interference.

Sound cards support digital audio in the following ways:

An internal connector on the sound card connects to a digital audio output connector on a CD/DVD drive. Through this connection, you can play CDs directly through the sound card.

An internal connector on the sound card sends HD audio, such as from a DVD or Blu-ray disc, to an audio pass-through on a video card. This allows the HD audio signal to be combined with the video signal through an HDMI connector.

Sony/Philips Digital Interface Format (S/PDIF) is a consumer standard for digital audio. These external connectors allow input and output between other digital audio-capable devices.

Additional ports

In addition to audio input and output ports, some sound cards also include the following ports:

Midi/joystick port to interface with Midi sound devices or game controllers.

Firewire.

Some high-end audio cards include HDMI video processors and video output, combining the features of an audio card with a video card. The sound card might have 1 or 2 HDMI ports (for input and/or output).


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Sound card drivers and other software save digital audio into several different file types. Common file types include:

WAV (Windows standard), a widely used and compatible file type.

AIFF (Audio Interchange File Format), the Macintosh equivalent of the WAV.

AU (UNIX standard), supported by most Web browsers.

MP3 (MPEG-1 Layer 3), a highly effective audio compression standard.

AAC (Advanced Audio Coding), also known as MPEG-2, a compression expected to replace MP3.

RA or RAM (Real Networks), developed for streaming audio files. Requires proprietary software.

WMA (Windows Media Audio), a highly compatible standard developed to compete with Real Audio.

MIDI, not a true audio file, but contains data to reproduce sounds through electronic synthesis.

Be aware of the following when configuring system sound:

Many motherboards include a built-in sound card. Use the connectors on the motherboard faceplate to connect components using the built-in sound card.

Sound cards are typically added to a computer using PCI or PCI-e slots. Some sound cards also connect through USB, and sound cards for laptops that lack integrated sound can use PCMCIA or ExpressCard slots.

When installing a sound card using an expansion slot, edit the CMOS settings and disable the built-in sound card.

To hear sound from an audio CD played in a PATA optical drive, be sure to connect the audio cable from the optical drive to the connector port on the sound card (or motherboard for built-in sound).

After installing the sound card, install the drivers and other software that came with the sound card.

Use the Sound applet in the Control Panel to: o Configure settings for sound card connections such as speakers, audio input,

and microphone. o Identify the sources that you want to record. o Configure sounds to play with system events or to play a sound to test your

configuration.

An audio codec is a specific method of formatting sound files. Common codecs include WAV, WMV, AIFF, and MP3. To play sounds saved using these formats, your computer must have the corresponding codec installed.

o You can see the list of installed codecs in System Information. o By default, Windows comes with common codecs installed. Other codecs

might be installed as you add other software.

To troubleshoot sound problems, try the following:

Make sure that the speakers are connected to the sound card and that the speakers have power.

Check the volume setting on the speaker and the back of the sound card (if present).

Check software sound settings. Verify that the sound is not muted and check mixer settings.

If some files play but others do not, make sure you have the right codecs installed for playing that file type.

If you are working with a built-in audio interface, verify that it is correctly configured in your BIOS. If you have installed an add-in card, make sure the built-in audio is disabled.


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If no sound plays, make sure the card is seated, check for resource conflicts, and update the drivers if necessary.

Ensure that the sound card is not experiencing Electromagnetic Interference (EMI) from the disk drive or power supply. To remedy this problem, move the affected card to an expansion slot located away from the source of EMI.

Sound cards provide input and output ports for connecting external audio-related devices to the computer. Some of these devices and ports are listed below:

Port Description

Mini TRS

Cable

Female ports

Mini TRS ports on the sound card accept 3.5mm plugs for analog audio input and output. The number of ports on the sound card depends on the type of input/output support such as the number of speaker channels, or microphone or line in support.

Ports are often labeled with text or graphic indicate the type of input or output expected. Standardized color coding might also be helpful in determining the proper connection.

Pink = Mic In (Mic Level)

Light blue = Line In (Line Level)

Lime green = Line Out, front speakers or headphones

Black = Line Out, rear speakers

Orange = Line Out, center and surround speakers

Although these colors are standard, be sure to consult the sound card documentation for specific details.

Toslink

Cable

Female port

A Toslink connector is used with digital optical input or output for S/PDIF audio.

RCA

An RCA connector on a sound card is usually used for coaxial digital input or output for S/PDIF audio. While RCA connectors can be used for


42

Cable

Female port

analog audio, RCA connectors on a sound card are normally used for S/PDIF digital audio.

DB-15

Cable

Female port

A DB-15 connector on a sound card is used to connect to MIDI devices or game joysticks.

Firewire

Cable

Female port

Some sound cards include one or more Firewire ports. These ports function as normal Firewire ports for connecting a variety of devices.

HDMI

Female port

A sound card with an HDMI port is capable of sending HD audio to an HDMI device. Some sound cards are able to output video, or combine a video signal from a video card and output the combined audio/video signal through the HDMI port.


You installed a PATA DVD drive, but when you play a CD no sound is played on the sound card. Other sounds play fine. What should you do to correct the problem?

What might you need to do to play AIFF files on a Windows computer?

What color typically indicates the speaker port on a sound card? What color is used for the microphone?


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Which connectors are used for digital S/PDIF audio?

What is a DB-15 connector on a sound card typically used for?

Section 3.10: Cooling

The normal operation of computer components produces heat. As components get smaller and the operating frequencies increase, so does the amount of heat generated by each component. Overheated components might cause intermittent errors, and the consistently-high temperatures can eventually make components fail.

The table below lists several methods you can use to cool the system.

Component Characteristics

Heat sensors

Most newer motherboards include the following heat sensors:

Processor sensor, located on the circuit board underneath the processor.

System case sensor, located somewhere inside the system, either on the motherboard or on a cable attached to the motherboard.

Room temperature sensor, usually connected to the motherboard by a cable and mounted on a case slot.

Special software can monitor the temperature levels and be configured to send warnings when high temperature conditions exist. The BIOS in most motherboards can also be configured to automatically shut the system down when a thermal threshold that you configure is exceeded.

Fans

The computer case is actually a pressurized system with a carefully-designed path for air to flow.

Intake fans create airflow by either blowing or sucking airflow across the motherboard and components.

Outtake fans pull warm air from inside the system.

On many systems, the power supply fan performs either intake or outtake functions.

The system case covers as well as expansion card covers must be on to ensure sufficient cooling. Otherwise, airflow and pressure will be negatively affected.

Dust and debris must be kept to a minimum inside the case.

Fans are also used in conjunction with heat sinks to improve cooling. Hard drive coolers are often a set of fans that attach to hard drives.

Heat sink

Heat sinks attach to components, increasing the surface area exposed to the air, essentially pulling heat from the components. Cooling can also be increased by adding a fan to the top of the heat sink to pull heat away from the heat sink. Common components that benefit from heat sinks include:


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Processors. All new processors require a heat sink and fan. In addition, use a thermal pad or thermal grease between the processor and the heatsink to improve heat transfer.

Video card chipset.

Motherboard chipset, especially when the motherboard has integrated video.

Memory. Heat spreaders make contact with the memory chips to dissipate heat. Faster, high-performance memory often requires heat spreaders.

Rounded cables

Older internal IDE and SCSI cables are flat and can restrict the airflow inside the case. To maximize cooling, keep cables organized and consider using rounded cables to maximize airflow.

Liquid cooling

For high-performance and gaming systems, you can install a liquid cooling system to improve cooling of devices such as the processor, chipset, and hard drives. The liquid cooling system replaces the heat sink and fan with a device that circulates a liquid coolant, much like a car's radiator.

Room temperature

The outside air temperature should range roughly between 45 and 90 degrees Fahrenheit. Maintaining a low room temperature ensures that heat generated by computers is dissipated, and also provides cool air that can be pulled into the system for cooling.

Ventilation To maintain proper air flow, keep any air intake or outlets free from obstructions. This might mean ensuring that nothing is close to the fans and vents on computers, laptops, monitors, and other devices.

Issues related to insufficient cooling are typically random errors or system lockups that are difficult to identify. One tool you can use to troubleshoot cooling problems is freeze spray. If a system is starting to fail due to overheating, spraying it with freeze spray reduces the temperature and could restore it to normal functionality. If the problem goes away after spraying a suspected component, implement additional cooling solutions for that component.


How does adequate cooling improve performance and extend the life of components?

How does organizing and attaching cables and wires in and around a computer system help with internal airflow?

Why should you keep the system case cover on during normal operations?

When might you want to add liquid cooling to a computer?

What is the difference between a heat sink and a heat spreader?

What is the function of a thermal pad? When should it be used?

section 3.1: cases and form factorscptsrv.ptc.edu/localuser/wctel/4_mod3.pdf · ©2012 testout...

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