CPUs and power supplies

Unit objective: Identify CPU characteristics and install

power supplies

Topic A

Topic A: CPUs Topic B: Power supplies

Central processing unit (CPU)

“Brains” of your PC Processes instructions, manipulates data,

controls interactions of other circuits Contains:

– A control unit– One or more

execution units– Registers– Single-core vs.

multi-core processors

CPU performance

Instruction — Low-level, hardware-specific command

Rated in millions of instructions per seconds (MIPS)

Rated according to clock speed Older CPUs — One clock cycle/

one instruction Newer CPUs — One clock cycle/

many instructions

CPU design characteristics pg 2-5

Addressable RAM Bus, address Bus, data Bus, internal Cache Clock speed Data bus width Dual Independent Bus (DIB) Front-side bus speed

continued

CPU characteristics, continued

GPU Hyperthreading Multimedia extensions (MMX) Multiprocessing Overclocking Pipelining Superscalar Throttling Virtualization support

Multiple-processor support

Requires symmetric multiprocessing code for OS and applications

64-bit versions of Windows 7 and Windows Vista use NUMA– Non-uniform memory access is a computer

memory design used in multiprocessing, where the memory access time depends on the memory location relative to a processor.

– With NUMA, a processor can access its own local memory faster than non-local memory (memory local to another processor or memory shared between processors).

– The benefits of NUMA are limited to particular workloads, mainly on servers

Processor specifications

Most common manufacturers:– Intel– AMD

Primary specifications– Clock speed, front side bus speed,

addressable RAM, Cache Size

Bus width specifications– No of bits which can be processed

Internal specifications– Voltages used by chips

Inside the case

Chipsets CPU packaging Slots

Chipsets

Memory control System bus functions Audio functions Video display functions System management functions

Northbridge and Southbridge

Two most important components of a PC chipset

Northbridge controls interactions between the CPU, memory (including cache), AGP and PCIe video control circuitry, and the Southbridge

continued

Northbridge/Southbridge, continued

Southbridge controls interactions between buses and devices not controlled by the Northbridge– PCI expansion bus– Floppy drive controller– Serial port– Parallel port– PS/2 keyboard and mouse ports– USB and FireWire– BIOS and CMOS

CPU packaging

Chip = die A package is made up of

– Die– Plastic, metal, or ceramic case– Wires or connectors– Support chips– Cooling components

PGA package

80486

SECC package

Pentium 3

Sockets and slots see pg 2-10

775 1156 1155 1366 940 AM2 AM2+ AM3 AM3+ FM1

F

Pentium with MMX CPU & Socket 7 socket

Typical cooling mechanisms Fans & Heat sinks and cooling fins Heat pipes

– (water heated, evaporates which causes it to move cooler water to area which is repeated)

Water pumps – (water pumped – more effective)

Peltier coolers – (device which gets colder when voltage applied)

Phase-change cooling – (like an AC unit)

Undervolting

Power supply and CPU fans

Power supply fan

Auxiliary fan

Cooling fins

Cooling fins and a fan

Other cooling techniques

Heat pipes — Small tubes filled with fluid Water pumps — Tubes filled with water,

moved away from CPU to outside case and through cooling fins

Peltier coolers – Electronic device that gets colder when voltage

is applied– Non-convection– Connected directly to CPU– Can be combined with water coolers

continued

Other cooling techniques, continued

Phase-change cooling– Vapor compression– Gas to liquid– Liquid absorbs processor heat and evaporates– Gas returned to compressor– Cycle begins again– More efficient than water cooling systems– Generate significant noise

Undervolting– Less power; less heat– Can cause system problems

Topic B

Topic A: CPUs Topic B: Power supplies

Characteristics of electricity

Electricity — Flow of electrons Conductor — Permits flow of electricity Insulator — Inhibits flow of electricity Voltage — Force of electricity caused by

difference in charge at two locations– Measured in volts– Also called “potential” or “potential difference”– Officially designated as uppercase V– May see it as lowercase v

continued

Characteristics, continued

Current — Measure of the flow of electrons past a given point – Measured in amps, or amperes– Must be a complete circuit (closed

circuit)– Direct current — Flows in one direction,

at constant voltage, through circuit – Alternating current — Flows repeatedly

back and forth through the circuit, at constantly varying voltage levels

continued

Characteristics, continued

Resistance — Force that opposes the flow of DC through a conductor

• Measured in ohms (Ω)

Impedance — Like resistance, but applies to AC

Power • Measured in watts• Calculate by multiplying voltage by current

Energy — Electrical power delivered over time

Electricity

Current can kill The 1–10–100 rule

– You can feel 1mA (1 milliamp)– 10mA enough to make muscles contract– 100mA enough to stop your heart

Safety precautions

Don’t touch exposed contacts Touch only insulated handles of tools Leave covers on equipment Work one-handed Don’t insert anything into wall outlets Remove jewelry, watches, etc. Keep hands clean and dry Don’t work in wet surroundings

PC power supply

Converts AC wall voltage to DC voltages for PC components

Includes a fan Provides some conditioning functions Can maintain power during brief drops and

outages

Power supply specifications

Rated by DC power output in watts– Modern systems typically =>600 watts– Older systems <200 watts

Rating isn’t an indicator of power draw– Most power supplies will only draw the

power which is needed to supply internal components

– Some less efficient power supplies will however draw full power and waste electricity

Typical power requirements

Motherboard 30 W

Memory 10 W per 2 GB*

CPU 45–145 W or more

Hard drive 5–15 W

CD-ROM drive 5–20 W

Floppy drive 5–10 W

Adapter card 5–30 W

Standard outputs

+3.3 V 14 A AGP video cards, motherboard

-5 V 0.3 A ISA bus adapter cards

+5 V 30 A Motherboard, CD/DVD drives, hard drives, PCI adapter cards, Pentium III and earlier processors

+5 V 0.85 A “Soft power” switch

-12 V 1 A Older network adapters and serial ports

+12 V 12 A CD/DVD drives, hard drives, Pentium 4 and Athlon processors, motherboard

Power watt calculator http://extreme.outervision.com/PSUEn

gine

Sizes

Form factor– AT– ATX– Micro-ATX

SATA power connector

For Serial ATA drives

Peripheral power connector

Molex connector Typically used to connect hard drives and

optical drives

Floppy power connector

Berg connector Smaller than Molex Typically used to connect floppy drives

Wire colors

Wire color Molex Berg SATA Voltage

Yellow 1 4 13, 14, 15 +12 V

Red 4 1 (optional) 7, 8, 9 +5 V

Black 2 and 3

2 (optional) and 3

4, 5, 610, 11,12

Ground

Orange 1, 2, 3 +3.3 v

Motherboard power connectors

Dual power connectors (P8/P9)

Single power connector

Voltage selection

Dual-supply units – can adjust the power supply to run from 110 or 220

– 110-120– 220-240

Unit summary

Identified CPU characteristics and installed power supplies