Computer Architecture

By

Chris Van Horn

CPU Basics

• “Brains of the Computer”

• Fetch Execute Cycle• Instruction

Branching

Control Unit

• Manager• Sends signals to

other devices telling them what to do

System Clock

• Signals when it is ok to perform work

• Cannot base CPU performance strictly by system clock

• Computer A: 12 cycles/instruction 1 Ghz

• Computer B: 3 cycles/instruction 250 MHz

Registers

• User Registers

• Control Registers– Program Counter– Instruction Register– Status Flag– Stack Pointer

ALU

• Where the real work happens– Adder– Multiplier– Shifter– Etc.

The Bus

• Provides Transportation– Data– Control Signals

• 3 Parts of the Bus• Other Bus Types• Master/Slave

relationship

Interrupts

• Interrupts processor when something needs its attention

• Threading

Pipelining

• Works like an assembly line

• Potential for large speed increase

• Long vs. Short Pipelines

• Drawbacks

Memory

• Hierarchy– Registers– Cache

• Level 1• Level 2

– Main Memory– Magnetic Disks

Multi Core Fun

• Why multi core?

• Why not just jack up the clock speed?

Intel

Intel Multi-core Technology

• Hyper-Threading

• Dual Core

• Core Duo

Hyper-Threading

• Dual core for the poor

• Processor runs two threads at once

Intel Dual Core

• Two Complete Cores running at same frequency

• Intel Pentium D– 2.8 – 3.4 GHz– FSB 800 MHz– Cache (per core)

• 900 Series 2MB• 800 Series 1MB

Intel Core Duo

• Replacement for Pentium M

• Specs– 2MB L2 cache

shared– 1.5 – 2.16 GHz– FSB 667 MHz

AMD

AMD Dual Core Technology

• Design Started Early• Direct Connect

Architecture• Operton Dual• Athlon Dual-Core X2

Opteron

• Specs– 1.8 – 2.4 GHz– L1 cache 64 KB per

core– L2 cache 1 MB per

core– FSB 1GHz

Athlon Dual-Core X2

• Specs– 2.0 – 2.4 GHz– L1 Cache

• 128 KB instruction• 128 KB data

– L2 Cache• 1-2MB per core

– 1 GHz FSB

Dual-Core Duel

• AMD challenges Intel to a Duel (Opteron Vs. Xeon)

• Intel Refuses• Tests Run by SPEC

(Standards Standard Performance Evaluation Corporation )

Test Results

• AMD declared itself the winner• Lack of Results• Reporting may be skewed

CNET X2 vs. Pentium D

• CNET independent test

• AMD won every round of tests

• Why?

Tests Run

• Everyday Computing– Office Productivity (SysMark Scores)– Internet Content Creation (SysMark Scores)

• Gaming– Halflife 2(fps)

• Multitasking– Encoding Video while Virus Scanner running (time to complete

both)• Photo Editing

– Photoshop (resizing large photos)• MP3 Encoding

– iTunes (time to encode album)• Video Encoding

– Sorenson Squeeze 4 (time to encode video)

Price Vs. Performance