© 2007 the mcgraw-hill companies, inc. all rights reserved microprocessors chapter 1 part 3

© 2007 The McGraw-Hill Companies, Inc. All rights reserved

MicroprocessorsChapter 1 part 3


Overview

• In this chapter, you will learn how to– Identify the core components of a CPU– Describe the relationship of CPUs and RAM– Explain the varieties of modern CPUs– Identify specialty CPUs– Install and upgrade CPUs


Central Processing Unit (CPU)Core Components


Concepts

• The CPU (Central Processing Unit) works as a very powerful calculator

• CPUs are not very smart…just very fast at manipulating zeroes and ones


External Data Bus

• The CPU communicates with the outside world using the external data bus (EDB)

– The EDB is made up of tiny wires– The state of a wire is expressed in a binary format,

with zeroes and ones– Each discrete setting (series of zeroes and ones

representing the state of the wires) of the EDB is a line of code in a program


Registers

• Inside the box are registers (temporary storage locations)

• The four general-purpose registers found in all CPUs are AX, BX, CX, and DX

10000101

00110101

11001001

10100001


Codebook

• The man in the box needs one more tool: the codebook or instruction set – Called machine language– One command is a line of code– The complete set of commands for a processor is

its instruction set

Instruction Meaning1000 0000 Store next line in AX1001 0000 Store next line in BX1011 0000 Add AX to BX & store in AX1100 0000 Place AX on EDB


Codebook (Instruction Set)

Instruction Meaning1000 0000 Store next line in AX1001 0000 Store next line in BX1011 0000 Add AX to BX & store in AX1100 0000 Place AX on EDB

1000 0000 Instruction (store data in AX)0000 0001 Data (number 1)1001 0000 Instruction (store data in BX)0000 0010 Data (number 2)1011 0000 Instruction (add AX and BX and place in AX)1100 0000 Place AX on EDB


Clock

• The CPU does no work until told to—even though data may be on the EDB

• You need a buzzer to tell the man in the box to start– This is referred to as a

clock– A clock is actually a

stream of pulses

zz

10000101

00110101

Time to work

10000101

00110101


Clock

• A clock cycle is the time taken by the special wire to charge up– The CPU needs at least two clock cycles to act on

each command– A cycle is one complete up and down segment of

the sine wave

• The maximum number of clock cycles that can be handled by the CPU is called the clock speed


System Crystal

• The system crystal defines the speed at which the CPU and the rest of the PC operate– Quartz oscillator, usually soldered to the

motherboard

• Overheating results from overclocking the CPU (running it faster than its maximum clock speed)


In Summary

• The CPU is like a man in a box• The external data bus gets data in and out of

the CPU• Registers are used as temporary storage

inside the CPU• The instruction set is like a codebook • The clock defines the speed of the CPU

10000101

00110101

11001001

10100001


Modern CPUs

CompTIA A+Essentials


CPU Overview

• Several specification are used to describe and compare CPUs:– Make (Intel, AMD) – Model (Pentium, Athlon, etc.) – Packages, or how it’s mounted (PGA, SEC, SEP)– External speed (speed of crystal)– Multiplier (applied to crystal)– Cache (L1 and L2) – Internal speed (speed when crystal multiplied)– Pipelining– Hyper-threading

• We’ll cover these in older and newer CPUs


Manufacturers

• Two main CPU makers– Intel– AMD

• CPUs might look similar, but they are not interchangeable


Common CPU Packages

• Pin grid array (PGA)– Most common– Number of pins vary by processor– Plugs into sockets that vary by processor

• Single edge cartridge (SEC)– Single edge processor (SEP) is similar– Processor mounted on board– Board plugs into motherboard

• Zero insertion force (ZIF)– Allows processor to be easily inserted– Arm locks processor in place


Pentium CPU—The Early Years

• CPU makers have added a large number of improvements over the years– Larger external data buses– Larger address buses– Faster clock speeds

• Intel introduced the Pentium CPU in the early 1990s– 32-bit registers– Speeds up to 300 MHz– Ability to run multiple programs at once– Access super-fast cache RAM– Processes two or more lines of code at the same

time


32-bit Addressing

• Current operating systems are referred to as 32-bit (232)– Can directly address 4 GB of memory

• Early Pentiums had 32-bit address bus

• Newer CPUs have 36-bit address bus– 236 allows addressing 64 GB of RAM– Some 32-bit operating systems address the extra

memory via “extensions”– Memory is swapped in and out of the 4 GB base as

needed


Pipelining

• A pipeline is a series of steps taken by the CPU to process a command

• Pipelining is the process of processing more than one command at a time through the use of separate sets of circuitry– Works like an assembly line– Commands go through the processor on a

“conveyer belt”– Enables the processor to work on more than one

thing at a time


Cache

• Cache is separate storage area used for quick access of data

– CPU runs faster than RAM

– Using a faster RAM cache close to the CPU helps the CPU run without waiting

– L1: close to the CPU and fastest

– L2: faster than RAM

1011 0101

1001 00011011 01100001 11011101 11011100 01111001 11111100 1010

RAM Cache

RAM

CPU


L2 Cache

• L2 was originally on the motherboard– Referred to as external

cache– Not uncommon on

today’s CPUs

• Size of the cache varies from 0 to 1 MB


Clock Speed and Multipliers

• The clock is derived from the crystal– Referred to as external

speed

• Clock is multiplied and CPU runs at quicker speed– CPU runs at much quicker

multiplied speed• 66 MHz crystal • Sent through a 2X multiplier • Gives a 132 MHZ CPU

Original clock

Clock with 2x multiplier

Has twice as many cycles for CPU to operate with


CPU Voltages

• Older CPUs needed 5 volts– CPU voltage was reduced to 3.3 volts

• Later improvements reduced voltage even more with no single standard– Smaller size resulted in lower voltage and smaller

chips– Voltage regulator module (VRM) is a small card that

enables a CPU to standardize voltage regulators– CPU reports voltage requirements with CPUID


Older CPUs

Early Pentiums

AMD K5 Pentium Pro

Ext. speed 50–66 MHz 50–75 MHz 60–66 MHzInt. speed 60–200 MHz 60–150 MHz 166–200 MHzMultiplier 1x to 3x 1.5x to 2x 2.5x to 3xL1 16 KB 16 KB 16 KBL2 256 KB,

512 KB, 1 MBPackage PGA PGA PGASocket Socket 4, 5 Socket 7 Socket 8Remarks High-end

systems


Improvements

• Out-of-order processing– Enabled processors to predict data that was needed– 90% accuracy in pulling the correct data

• On-chip L2 cache– On the same package, but not necessarily on the

same chip


Bus Types

• Frontside bus– Address bus and external data bus are combined

together between the CPU, MCC, and RAM

• Backside bus– Connection between the CPU and L2 cache

• Remember that L2 cache used to be external cache but is now internal to the CPU housing

CPU

L2 Cache

RAMMCC

Frontside bus

Backside bus


Older CPUs

Later Pentiums

Pentium II AMD K6

Ext. speed 66–75 MHz 66–100 MHz 60–100 MHzInt. speed 166–200 MHz 233–450 MHz 200– 550 MHzMultiplier 2.5x to 4.5x 3.5x to 4.5x 3.5x to 5.5xL1 32 KB 32 KB 32 or 64 KBL2 512 KB 0 to 256 KBPackage PGA SEC PGASocket Socket 7 Slot 1 Socket 7Remarks AMD & Intel

Split


Pentium Improvements

• MMX (multimedia extensions)– Designed for graphical applications

• Increased clocks and multipliers– Up to 4.5x

• Pentium II– Faster than Pentium Pro – Used SEC

• AMD K6– Proprietary 3DNow!– Requires a Super Socket 7


Older CPUs

Intel Celeron (P II)

Pentium III AMD Athlons

Ext. speed 66 MHz 100–133 MHz 100–133 MHzInt. speed 266–700 MHz 450 MHz–1.2

GHz500MHz–1GHz

Multiplier 4x to 10.5x 4x to 10x 5x to 10xL1 32 KB 32 KB 128 KB

L2 0 to 128 KB 256–512 KB 512 KBPackage SEP, PGA SEC-2, PGA SECSocket Slot 1,

Socket 370Slot 1, Socket 370

Slot A7


Older CPUs

• Celeron– Offshoot of Pentium II for

the low-end PC

• Pentium III– Intel’s answer to 3DNow! by

AMD

• AMD Athlon– SEC package used slot A


More Current CPUs

AMD Athlon AMD Duron Pentium 4Codename Thunderbird WillametteProcess 180 nm 180 nm 180 nmWattage 38–75 21–57 49–100Ext. speed 100–133 MHz 100 MHz 100–133 MHzInt. speed 650 MHz–

1.4 GHz650 MHz–1.8 GHz

1.3–2 GHz

Multiplier 6.5x to 14x 6.5x to 13.5x 13x to 20xL1 128 KB 128 KB 128 KBL2 256 KB 64 KB 256 KBPackage PGA PGA PGASocket Socket A Socket A Socket 423 or 478


IT Technician

Processing and Wattage

CompTIA A+Technician


Processing and Wattage

• Wattage is a measure of power– Goal is to consume as little power as possible

while still having a powerful CPU– Solution: make it smaller so it takes less voltage;

less voltage is less wattage

• Processing– Measures thickness of wafers– Some of today’s processors are 65 nanometers

• About as thick as 455 hydrogen atoms• Or 1/3077th of the width of a human hair

Hydrogen atom


Pentium Competitors

• AMD Athlon Thunderbird– Double-pumped frontside bus doubled the data rate

without increasing the clock speed– Returned to PGA with Socket A

• AMD Duron– Generic name given to all lower-end Athlon processors– AMD’s competitor to Intel’s Celeron for the low-end PC

• Intel Pentium 4 (Willamette)– Completely redesigned core called NetBurst– Used 20-step pipeline – Quad-pumped frontside bus


More Current CPUs

AMD Athlon AMD AthlonCodename Palomino ThoroughbredProcess 180 nm 150 nmWattage 60–72 49–70Ext. speed 133 MHz 166 MHzInt. speed 1.3–2.2 GHz 1.3–2.2 GHzMultiplier 13x to 16.5x 13x to 16.5xL1 128 KB 128 KBL2 256–512 KB 256–512 KBPackage PGA PGASocket Socket A Socket A


More Current CPUs

Pentium 4 Pentium 4 Pentium 4Codename Northwood Prescott Cedar MillProcess 130 nm 90 nm 65 nmWattage 45–68 ~84 86Ext. speed 100 MHz 133 MHz 200 MHzInt. speed 1.3–3.8 GHz 1.3–3.8 GHz 1.3–3.8 GHzMultiplier 13x to 23x 13x to 23x 13x to 23xL1 128 KB 128 KB 128 KBL2 256, 512 KB 256, 512 KB 256, 512 KBPackage PGA PGA PGASocket Socket 478 or

775Socket 478 or 775

Socket 478 or 775


Newer Processors

• AMD Athlon XP (Palomino and Thoroughbred)– Enhanced version of the Athlon core processor

• Intel Pentium 4 (Northwood, Prescott, Cedar Mill)– Increased frontside bus to 800 MHz– Introduced hyperthreading

• Hyperthreading– Looks like two CPUs

to the operating system


More Current CPUs

AMD Athlon XP AMD AthlonCodename Palomino ThoroughbredProcess 180 nm 150 nmWattage 60–72 49–70Ext. speed 133 MHz 166 MHzInt. speed 1.3–2.2 GHz 1.3–2.2 GHzMultiplier 13x to 16.5x 13x to 16.5xL1 128 KB 128 KBL2 256–512 KB 256–512 KBPackage PGA PGASocket Socket A Socket A


More Current CPUs

Athlon XP Pentium 4Codename Thorton/Barton Extreme EditionProcess 130 nm 130, 90 nmWattage 60–70 85–115Ext. speed 133, 166, 200 MHz 200, 266 MHzInt. speed 1.6–2.2 GHz 3.2–3.7 GHzMultiplier 10x to 16x 14x to 17xL1 128 KB 128 KBL2 256, 512 KB 512 KBL3 2 MBPackage PGA PGASocket Socket A Socket 478 or 775


Mobile Processors

• Mobile processors– For laptops– Use less power to overcome problems of heat and

power requirements

• Utilize throttling– Previously called system management mode

(SMM)– Allows a CPU to slow down during low demand

times– Intel calls it SpeedStep– AMD calls it PowerNow!


More Processors

• Intel Xeon processors

– Series of powerful CPUs– Massive L2 caches– Xeon is codeword for high-end– Can easily be used in symmetric multiprocessing

systems (multiple physical processors)– Early Xeon used slots– Later Xeons went back to PGA packages


64-Bit Processors

• 64-bit processing refers to a 64-bit address bus– We already had 64-bit external data buses

• Intel Itanium processors– Itanium was Intel’s first 64-bit chip– Itanium II is made for the PC


64-Bit Processors

• AMD Opteron processor– Runs both 32-bit and 64-bit code

• Athlon 64– First desktop 64-bit processor– Backward-compatible with 32-bit programs– Two main groups (130 nm and 90 nm)

• AMD Sempron CPUs– Less cache than the Athlon 64– Offer a tradeoff between price and performance


Dual-core CPUs

• Due to practical limit of ~4 GHz in clock speeds, alternatives were sought

• Dual core features two CPUs on same chip

– Pentium D– Athlon Dual Cores


Dual-core CPUs

Pentium D Athlon Dual CoreCodename Smtihfield/PreslerProcess 90, 65 nm 90 nmWattage 95–130 89–110Ext. speed 166, 200 MHz 200 MHzInt. speed 2.6–3.6 GHz 2–2.4 GHzMultiplier 14x to 20x 10x to 12xL1 Two 128 KB 128 KBL2 Two 1 or 2 MB Two 512 KB or 1 MBPackage 775 LGA PGASocket Socket LGA 775 Socket 939 or AM2


Intel Core CPUs

Intel Core Intel Core 2Codename YonahProcess 90, 65 nm 90 nmWattage 95–130 89–110Ext. speed 166, 200 MHz 200 MHzInt. speed 2.6–3.6 GHz 2–2.4 GHzMultiplier 14x to 20x 10x to 12xL1 Two 128 KB 128 KBL2 Two 1 or 2 MB Two 512 KB or 1 MBPackage 775 LGA PGASocket Socket LGA 775 Socket 939 or AM2


Installing CPUs


Why Replace a CPU?

• Cost– Chances are you’ll need to replace the

motherboard as well as the CPU—is it worth it?

• Cooling– Faster CPUs will probably need better cooling

• Performance– Faster CPUs may not be the best answer to

speeding up your PC• Many times you really need more RAM


The Right CPU

• Consult your motherboard manual– You need a CPU that will fit

in the socket or slot on your motherboard

• Buying a CPU– Most stores will not accept

returns– Retail-boxed CPUs are genuine and come

with a fan– Lots of illegal CPUs on the market


CPU Installation Guidelines

• Don’t touch the pins (ESD)

• Match the notch and dot printed on the corners of the CPU…they must line up– Incorrectly installing

your CPU may destroy the CPU and/or motherboard!


CPU Installation Guidelines

• Use a heat sink compound

• Install a fan on top of the CPU after the CPU has been inserted into the socket


Plugging in the CPU Fan


The Art of Cooling

• Modern CPUs need to be kept cool– OEM fans are included in

retail-boxed CPUs

– Specialized fans usually exceed OEM fans

– Liquid cooling works by running a liquid (usually water) through a metal block that sits on top of your CPU to absorb heat


Overclocking

• Overclocking is running a CPU at a speed higher than rated– Voids the warranty– Black market exists

© 2007 the mcgraw-hill companies, inc. all rights reserved microprocessors chapter 1 part 3

Documents

data number

bx store

place ax

upthe cpu

edbclockthe cpu

onesexternal data bus

clocka clock

boxthe external data