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. Man in the Box • Visualize the CPU as a man in a box. • He will gladly perform anything you want him to do, but he can’t see or hear anything outside the box. • How can we communicate with him? Is anyone out there? We need some way to talk to the guy inside the box

6. Talking to the Man • Imagine 16 lights • 8 on the inside and 8 on the outside • When an inside light is on, the corresponding outside light is on. We can switch these lights on and off. • This communication system is like the external data bus

7. On On On On On Off Off Off 1 1 1 1 1 0 0 0 Talking to the Man • In reality, a lot of little wires flash on or off • Voltage is applied or not • Represented not as on, on, off, off…but as 1, 1, 0, 0…

8. External Data Bus • The CPU communicates with the outside world using the external data bus (EDB) • Instead of light bulbs, 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

9. 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

10. 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

11. Codebook (Instruction Set)

12. 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

13. 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

14. 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)

15. 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

16. Memory

17. Memory • Memory is a device that holds binary data • Memory was first stored on paper cards and then on magnetic cards and magnetic tapes • Problems • Serial access • Slow • Random access memory (RAM) to the rescue!

18. RAM • RAM is organized similar to a spreadsheet • Data can be read or written to by addressing the RAM location • Typically represented as KB, MB, or GB • Volatile—zeroes outwhen power lost

19. MCC Memory Controller Chip • The memory controller chip (MCC) is a device that facilitates the flow of data from the RAM to the CPU

20. MCC Address Bus • The address bus enables the CPU to control the MCC • Another set of wires in addition to the external data bus • Used by the CPU to tell the Northbridge which line of code it wants from RAM

21. Address Bus • The number of wires in the address bus determines the maximum amount of RAM the CPU can handle • An 8088 had 20 wires, which provided 220 combinations (1,048,576 or 1 MB) • Many current CPUs use 36 wires, which provide 236 combinations (68,718,476,736 or 64 GB)

22. Terminology • Bits are represented as b (i.e., Kb) • Bytes are represented as B (i.e., KB)

23. Decimal Compared to Binary 643 Decimal 101 Binary 102 101 100 22 21 20 100 10 1 4 2 1 0 1 1 6 4 3 4 + 0 + 1 + 5 Decimal 600 + 40 + 3 643

24. Modern CPUs CompTIA A+Essentials

25. 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

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

27. 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

28. 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

29. 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

30. 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

31. 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

32. 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

33. 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

34. 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

35. Older CPUs

36. 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

37. 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

38. Older CPUs

39. 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

40. Older CPUs

41. 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

42. More Current CPUs

43. IT Technician CompTIA A+Technician Processing and Wattage

44. 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

45. 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

46. More Current CPUs

47. More Current CPUs

48. 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

49. More Current CPUs

50. More Current CPUs