Ch 4 1

Central Processing Unit (CPU)

Computer Service and Repair Chapter 4

Ch 4 2

Instructions and Data

• The CPU is the computer’s brain• In 1978 had 27,000 transistors now they have over

2.5 billion• CPU follows commands called instructions• Instruction set is the set of basic commands all

CPUs follow– Add / subtract– Compare– Add one to / subtract one from– Get the next one, two, or, four bytes from– Put the next one, two, or four byte at

Ch 4 3

Instructions and Data (cont’d)• The Instruction Set is written in assembly language

– the lowest language level used to program a computer (one step up from machine language)

• A compiler is a program that translates higher level programs into machine language

• A register is a small pocket of memory in a CPU used to temporarily store data that is being processed– add number stored in register A to number stored in

register B place result in register C

Ch 4 4

CPU Operation

• CPU is in constant operation– Refreshing memory– Checking for communication from other devices– Monitoring system power– Performing other programmed duties– Checking IRQ status

Ch 4 5

CPU Operation (Cont’d)CPU Parts• Bus Unit: network of circuitry that connects all off

the other major components together• Instruction Cache: small temporary memory to

store incoming data and instructions• Decode unit: decodes instructions• Control Unit: controls overall operation of CPU• Arithmetic logic unit (ALU) performs math functions

• Register unit: composed of many separate storage units (register hold only one number or letter each)

Ch 4 6

CPU Operation (Cont’d)

Ch 4 7

CPU Operation (Cont’d)• Not all business conducted on a PC requires the use

of a powerful CPU– i.e. word processor

• Powerful CPU needs for graphic intense programs, weather, or CAD programs– i.e. 3D animation that requires redrawing every line of

image and calculations based on X,Y, & Z coordinates in fractions of a second

• To save CPU time data not requiring manipulation are now transferred directly to memory

• System clock send repetitive signal to all parts of system to keep data transmissions in step

Ch 4 8

CPU Operation (Cont’d)

• CPU speed is measured in hertz Hz (cycles per second)– Number of digital pulses per second

• Hertz is often referred to as frequency• Speed became important as user interface

switched from text to GUI• Each new generation of CPU operated on shorter

clock cycles (frequency)

Ch 4 9

Enhancing CPU Operation• In addition to speed CPU have Improved:• Local Bus: links devices directly to CPU

– RAM– Video card slots – Referred to as system bus or front side bus– Shortened bus reduces inductive reactance

• Cache– L1 cache is designed to run at same speed as CPU– L1 allows CPU to quickly process data– Two L1 Cache for each processor (one for instruction and one for

data)– L1 memory is most costly to produce– L1 is small on inexpensive processors

Ch 4 10

Enhancing CPU Operation (cont’d)

• L2 Cache: used to increase data from the processor to other parts of the motherboard– Originally separate from CPU mounted close on

motherboard– Moved in CPU with Pentium III

• L3 Cache:– Originally added to mother board to speed when

L2 moved to CPU– Now on CPU (shared between multi core CPUs)

Ch 4 11

Enhancing CPU Operation (cont’d)

• Floating Point Unit (FPU): a set of circuits in the CPU that replace the math coprocessor that was originally on the mother board

• Multiple Branch Prediction: guesses what data the CPU will need next instead of waiting for instructions to be issued (90% accurate)

• Superscalar execution: processing more than one instruction at a time

Ch 4 12

Enhancing CPU Operation (cont’d)

• Dynamic Execution: CPU looks ahead if an instruction can be carried out faster than the instruction preceding it, it is moved ahead an executed.

• Integrated Memory Controller: (IMC) Controls data flow in front side bus to / from RAM

• Integrated Graphics Processing: (GPU) enhances the ability of computer to produce video and 3-D images

Ch 4 13

Enhancing CPU Operation (cont’d)

• Dual Independent Bus (DIB): Two separate bus systems incorporated into the CPU– One for Main Memory– One for L2– Both buses are use simultaneously

• Simultaneous Threading– Thread is part of a software program that can be

executed independently– Multi-core processors use two threads per core (quad

core runs 8X as fast as single core)

Ch 4 14

Enhancing CPU Operation (cont’d)• Overclocking: running a CPU at frequencies higher than rated.

– Raises heat– Can / will damage CPU– CPU can accomplish more tasks in shorter time– Frequencies can be controlled by BIOS

• Turbo Boost Technology / Turbo CORE– Overclock CPU– Monitor temperature and energy use– Halts overclocking if temp gets to high– Intel provides free software (Intel Extreme Tuning Utility)

• Voids warranty• Intel does not recommend

Ch 4 15

Process Description Features• Reduced Instruction Set Computer (RISC): a CPU

Produced with fewer transistors and instruction– Inexpensive but fast– Software has carry modifications that allow for fewer

CPU computations– Used in IPad, Iphone, Android, auto engine controls,

TVs, airplanes, robots, and servers• Complex instruction set computer (CISC): A CPU

that processes complex mathematical formulas at increased clock speed

Ch 4 16

Process Description Features (cont’d)• MMX Processor: based on standard processor

with the addition of 57 commands.– Enhances ability of CPU to support graphic technology– Replaces functions of video and sound cards– MMX could mean Multi-Media eXtensions, Mtrix Math

eXtensions, or as Intel claims nothing at all• 32 bit vs 64 Bit (64 faster.)must have following:– BIOS must support 64 bit technology– 64 bit O/S– 64 bit drivers– Software written for 64 bit systems

Ch 4 17

Process Description Features (cont’d)

• Virtualization: a single physical CPU appear as multiple processors to the system software and the user.– Allows multiple operating systems, users, and

application software simultaneously– Normally applied to network servers

• System Management Mode: (SMM) Designed for laptops to save energy– Sleep– Auto shut down

Ch 4 18

Process Description Features (cont’d)

• Cool ‘n’ Quiet (Process throttling): adjust process speed and power consumption based on temperature and software usage. Fan speed may also be slowed

• Enhanced Intel SpeedStep Technology: When laptop is plugged in Runs on 2.6 GHz applied 1.3 volts overall power consumed is 30 watts. When on battery runs at 1.3 GHz and 1.2 volts overall power consumed 20.8 watts

Ch 4 19

Process Description Features (cont’d)

• CPU operating voltage has dropped from 5 Volts to less than 1 volt

• Processor Size (physical) has not changed significantly but the electronics have become more compact

• Moore’s Law: (1965) Gordon Moore cofounder of Intel predicted that computer calculating power would double every year. He has been pretty close (now takes about 18 months)

Ch 4 20

Processor Manufacturers

Three Biggest:• Intel is the dominate manufacture of CPUs

since 1970’s• AMD Intel’s biggest competitor.• VIA Technologies is not as large as Intel or

AMD make processors and motherboards with intel, AMD, and their own processors

Ch 4 21

Processor Evolution• Intel Pentium (1993): front side bus• Intel Pentium Xeon (Xeon 1998)– network servers– Hyper threading– Not designed for entertainment– Multiprocessors on each board ( blade servers)– Used in web servers, cloud storage, and networks

• Intel Celeron (1999) general purpose computers– Limited L1 and L2 counters high speed processor

results in less overall performance

Ch 4 22

Processor Evolution (cont’d)• AMD Athlon 64 (2002) uses 32 and 64 bit processing• AMD Opteron (2003)– for Network Servers – 64 bit– Can process 256 TB– Usually runs between 800 MHz – 2.6 GHz– 19 GB throughput

• AMD Sempron (2004)– Low cost computers– Two types (front bridge or HyperTranport)

Ch 4 23

Processor Evolution (cont’d)• AMD Athlon 64 X2 (2005) 64-bit dual core• AMD Athlon 64 FX (2006) introduced new socket• Intel Core Solo (2006) designed for laptops• Intel Dual Core (2006) Intel’s first dual core • Intel Dual Core 2 Duo (2006)Dual core, front bus,

variable L2• Intel Core 2 Extreme (2007) gaming, 8MB L2• Intel Core 2 Extreme Quad (2007) four processors

Ch 4 24

Processor Evolution (cont’d)

• Intel Core i3 (2011) minimal computing power for devices that use the cloud

• Intel Core i5 (2011) intermediate processor does not have Hyper-Threading good for average computer systems with limited multi-media editing capabilities

• Intel Core i7 (2011)High Performance CPU– Turbo boost technology– Hyper-Threading– Larges L3 Cache– Two types i7 & I7 Extreme (better graphics)

Ch 4 25

Processor Evolution (cont’d)• Intel Atom: Specialized for low power consumption and low heat– 32 and 64 bit– Single and dual core– Netbooks, tablets, smart phones

• AMD FX: Best AMD to Date– 4,6,or 8 core– 3-D graphics– Designed for over clocking– First CPU with 8 cores

• AMD A-series– A4, A6, A8, and A10 similar to Intel i3, i5, i7

• AMD and Intel are too similar to say one is better than the other must test specific software used to determine best for your use

Ch 4 26

Processor Affinity

• Processor Affinity is the ability to select the number of cores to apply to a software application– System and Software must be designed to operate

in the multi core environment– Software / system may lockup if mismatched– Deselect any number of processors from CPU 0 to

CPU 7 to run the software application in the Task Manager by selecting Processor Affinity

Ch 4 27

Processor Sockets

• Processor Sockets vary according into the number of electrical connections.

• AMD and Intel are not interchangable• AMD – Land Grid Array (LGA) Lands are small Flat

connectors• Intel – Pin Grid Array (PGA) connectors are pins• Originally techs pushed CPUs into Socket– Lands and pins could be damages easily

• Zero Insertion Force Socket (ZIF) has one or two levers the clamp onto pins or lands

Ch 4 28

Processor Performance

• CPU is not the only thing that affect system speed• Download and Use a CPU analyzer– CPU-Z is free – Download from Cupid– Will identify CPU– L1 and L2 size– Socket type– Core and bus Speed– more

Ch 4 29

Questions to ask before Upgrading CPU• What are you trying to achieve by upgrading CPU• Is the upgrade CPU compatible• Will Chip set and BIOS support the upgrade• Does the motherboard bus speed or chipset rather than

the CPU limit the increase in speed• Does the chipset support desired features of the new CPU

such as 3-D tech • Note:– Cables / Modems affect download speed– If main function is typing new CPU little effect– If gaming new CPU May help is motherboard and chipset support

it

Ch 4 30

Installing a Processor

• Remove cooling Device• Release locking lever(s)• Lift out CPU• Align pins (lands) to socket• Gently drop CPU into socket• Close locking levers• Reinstall cooling device

Ch 4 31

Installing a Processor

Ch 4 32

Cooling the Processor

• Electronic integrated circuits start to break down at 160 degrees F

• Three Type of Cooling– Simple heat sink and fan (most common)

• Heat sink paste

– Heat pipe cooling system (high performance)• Hollow tubes with liquid that vaporizes and condenses at the

heat sink and returns to CPU by capillary action

– Liquid Cooling System (very high performance)• Liquid is pumped rom CPU to a small radiator and back to CPU

(Most Expensive)

Ch 4 33

Heat Sink and Fan

Ch 4 34

Heat Pipe Cooling System

Ch 4 35

Liquid Cooling System

Ch 4 36

End of Chapter 4

Questions?