Microprocessors

1. Microprocessors Chapter 3

2. 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

3. Central Processing Unit (CPU)Core Components

4. 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

5. 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

6. 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 11001001 00110101 10100001

7. 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

8. Codebook (Instruction Set)

9. 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

10. 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

11. 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)

12. 10000101 11001001 00110101 10100001 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

13. CompTIA A+Essentials Modern CPUs

14. 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

15. Manufacturers • Two main CPU makers • Intel • AMD • CPUs might look similar, but they are not interchangeable

16. 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

17. 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

18. 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

19. 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

20. 1011 0101 1100 1010 1001 1111 1100 0111 1101 1101 0001 1101 1011 0110 1001 0001 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 RAM CPU RAM Cache

21. 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

22. 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

23. 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

24. Older CPUs

25. 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

26. 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 MCC RAM Backside bus Frontside bus

27. Older CPUs

28. 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

29. Older CPUs

30. 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

31. More Current CPUs

32. IT Technician CompTIA A+Technician Processing and Wattage

33. Processing and Wattage • Wattage is a measure of power • Goal is to consume as little power as possiblewhile 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

34. 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

35. More Current CPUs

36. More Current CPUs

37. 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 CPUsto the operating system

38. More Current CPUs

39. More Current CPUs

40. 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!

41. 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

42. 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

43. 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

44. 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

45. Dual-core CPUs

46. Intel Core CPUs

47. Installing CPUs

48. 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

49. 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

50. 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!