This document summarizes the history and generations of microprocessors from the early 1970s to the 2000s. It describes the key features and specifications of important processors like the Intel 4004, 8088, 286, 386, 486, Pentium, Pentium Pro, Pentium II, Pentium III, Pentium 4 and Itanium. Each generation brought performance improvements through higher clock speeds, increased transistor counts, cache memory, pipelining and other architectural enhancements. The document also discusses competing processors from AMD, Cyrix and others.

1. Microprocessor
Generations

2. The First Microprocessor
• Intel created the first microprocessor 4004 in 1971.
• Ran at a clock speed of 108KHz
• Contained 2,300 transistors and was built on a
10-micron process.
• Then came the Z-80 by Zilog in 1976 used in
TRS-80
• 6502 by MOS Technologies used in Apple-I and II.

3. The First PC
• In 1981 IBM introduced the IBM PC, which was
based on a 4.77MHz Intel 8088 processor running
the Microsoft Disk Operating System (MS-DOS)
1.0
– 30,000 transistor at 4.77MHz
– 16 bit internal registers (IA-16) /8 bit external data bus
– 20 bit address bus could address upto ________Bytes?
• All Processors are backward compatible, like P4,
AMD Athlon, etc.

4. Generation of Microprocessors
•
•
•
•
•
•
•
•
•
First Generation (P1)
Second Generation (P2)
Third Generation (P3)
Fourth Generation (P4)
Fifth Generation (P5)
Fifth Generation (P5)
Sixth-Generation (P6)
Seventh-Generation Processors
Eighth-Generation Processors

5. First Generation (P1)
8088
• A 40 pin microprocessor with the attributes of an 8-bit
and 16-bit processor. Internally it works with 16 bits
but data bus is 8-bits.
• 20-bit address bus - capable of holding 1 Meg
memory.
• Ran in real mode only
• Companion Coprocessor - 8087
– 8086
• Same as above only data bus is 8-bits.

6. Second Generation (P2)
80286
–
–
–
–
68 pin chip in various packages.
Backwards compatible with 8088 but much faster.
True 16-bit microprocessor.
Designed for multi-user, multi-task.
• Has special memory protection/management circuitry that
protects the various running tasks from each other and the
operating system.
– Operates in two modes:
• Real Mode - runs single tasks, addresses REAL memory up to
1 Meg.
• Protected Mode - runs multiple tasks, address up to 16 Meg
physical memory, plus it can address virtual memory.
– Virtual memory is really hard disk space being used as RAM.

7. Second Generation (P2)
80286
• Was available in different clock speeds.
• Companion Coprocessor - 80287

8. Third Generation (P3)
80386DX
– 32-bit (internally & externally) successor to
80286, 132-pins
– Had to do 16-bit and 8-bit I/O data transfers to
keep it compatible with older software and
peripherals.
– Could switch between real and protected memory
without a reboot.

9. Third Generation (P3)
This advanced memory management allow for ROM
shadowing, moving code out of ROM into faster
RAM.
– New addressing mode was developed called virtual
mode.
• Made the 80386 appear like multiple XT processors so multiple
programs could run at once.
• 80386SX
– 100 pin chip.
– Internally the same as a 80386DX, externally had 24-bit
address and 16-bit data bus.

10. Third Generation (P3)
Other Flavours of 80386
– 80386SL: used in laptops, had lower (L) power
consumption. Had external 32-bit address bus
like DX, but external 16-bit data bus like SX.
– AM80386SX and DX: AMD manufactured clone.
SX was like the SL.

11. Fourth Generation (P4)
80486DX:
– 168 pin
– Included
• math coprocessor
– synchronous with main processor and executes in fewer
cycles than previous math coprocessors
• 8KB Level 1 memory cache
– 90-95% zero wait states
• Reduced instruction-execution time
– average of two clock cycles per instruction compared to
previous of more than four clock cycles needed
• Burst-mode memory cycles

12. Fourth Generation (P4)
Other Flavours of 80486:
– 80486SX: same as DX except there is no
coprocessor. Companion coprocessor - 80487
– 80486DX2: the processor’s internal speed is
doubled.
– 80486DX4: the processor’s internal speed is
tripled.
– CX486SLC: Cyrix processor that is basically a
386SX.
– CX486DLC:Cyrix processor that is 486DX.
– CX486DRU2:Cyrix processor that is 486DX2.

13. Fourth Generation (P4)
AMD 486 (5x86)
• 486 that runs at 133MHz
• Some 486 motherboards support this chip
• Similar to Pentium 75
– AMD A80486DX2-80SV8B (40MHz x 2)
– AMD A80486DX4-100SV8B (33MHz x 3)
– AMD A80486DX4-120SV8B (40MHx x 3)

14. Fifth Generation (P5)
64-bit data bus
– 2 separate 8KB internal caches, 1 for instructions,
1 for data
– superscalar microprocessor, runs multiple
instructions simultaneously
• achieved by pipelining
– Pipelining breaks instruction cycle into small stages. Each
stage is capable of handling many instructions.
– Two pipelines in pentium, u-pipe and v-pipe
– Each pipeline has its own ALU

15. Pipelining
• Fetching and execution of each instruction is split
into many stages,
• all working in parallel.
• This allows the processing of up to five instructions
to be overlapped.

16. Pipelining
• In 8085 there was no pipelining.
• 8086 had enjoyed the first pipelining.
• In the 486 the pipeline stage is broken down even
further, to 5 stages as follows:
– 1. fetch (prefetch)
– 2. decode 1 (two stage decode)
– 3. decode 2
– 4. execute
– 5. register write-back (result goes to EAX)

17. pipelined vs. nonpipelined execution

18. Pipelining

19. Pipelining
Stage 1
Stage 2
Stage 3
Stage 4
Stage 5
Instruction
Fetch
Instruction
Decode
Operand
Fetch
Instruction
Execution
Write
Back
Stage 1
Stage 2
Stage 3
Stage 4
2
1
3
2
4
3
5
4
6
5
7
6
8
7
9
8
9
1
1
2
1
3
2
1
4
3
5
4
6
5
7
6
8
7
9
8
9
2
3
4
5
6
7
8
5
6
7
8
9
Stage 5
1
2
3
4
Time
9

20. heavily pipelining
• By heavily pipelining the fetching and
execution of instructions, many 486
instructions are executed in only 1 clock cycle
instead of in 3 clocks as in the 386.

21. Fifth Generation (P5)
Pentium First Generation:
– 273 pin package
– 60 & 66 MHz (same speed as motherboard)
– Same voltage as motherboard
Pentium Second Generation:
–
–
–
–
296 pin package
uses 3.3V
90/100/75120/133/150/166/200 MHz
could run simultaneously with second processor
• Symmetric Multi-Processing (SMP)

22. Fifth Generation (P5)
Pentium MMX:
–
–
–
–
Pentium Third Generation
Level 1 cache increased from 16 KB to 32 KB
External level 2 cache typically 256KB or 512KB
Addition of 57 instructions related to multimedia and
communication processing.
– Available in 166/200/266 MHz clock speeds.
– Requires different voltage level
• 3.3V for I/O
• 2.8V for core

23. Other Fifth-Generation Processors
• AMD
– K5
• Competes with Classic Pentium
• Offers an assortment of clock speeds and bus speeds
• Compatible with most motherboards that supported
Pentiums
– BIOS might need to be upgraded
– voltage level slightly different - 3.52V
• Available as:
– PR75, PR90, PR100, PR120, PR133, PR-166

24. Other Fifth-Generation Processors
Features:
•
•
•
•
•
16KB instruction cache
Dynamic execution
Five-stage RISC-like pipeline
FPU
Pin-selectable clock multiples of 1.5x & 2x
• IDT Centaur C6 Winchip
–
–
–
–
–
Socket-7 compatible
Speeds of 180, 200, 225, 240 MHz
Not superscalar
Slower with multimedia applications and games
Smaller, less power consumption

25. Sixth-Generation (P6)
Dynamic Execution
Dual Independent Bus Architecture
Better Superscalar Design
Pentium Pro:
– 387 pin package
– has on-board (included with the CPU but not
internal) L2 cache, either 256, 512KB or 1MB
running at full core speed

26. Sixth-Generation (P6)
Pentium Pro motherboards quite often have sockets
for two CPUs
– Recommended for applications that rely heavily on fast
access to cache memory
– Applications that focus on complex calculations, rather
than on servers, need this high-speed performance
– Does not perform well with older 16-bit legacy
applications written for DOS or Windows 3.x

27. Sixth-Generation (P6)
Pentium II
– Basically the same as Pentium Pro except
• Has MMX
• Same Level 1 cache size as Pentium MMX (32K)
• Package changed from PGA to Single Edge Contact (SEC)
cartridge
• L2 cache of 512KB at half core speed
SPEED
233 MHz
266 MHz
300 MHz
333 MHz
350 MHz
400 MHz
450 MHz
CPU CLOCK
3.5x
4x
4.5x
5x
3.5x
4x
4.5x
MOTHERBOARD SPEED
66 MHz
66 MHz
66 MHz
66 MHz
100 MHz
100 MHz
100 MHz

28. Sixth-Generation (P6)
Pentium II Xeon
– P6
• 512KB, 1MB, or 2MB of L2 Cache running at full
core speed

29. Sixth-Generation (P6)
Celeron
– P6 with no L2 cache
– Packaged in Single Edge Processor Package
(SEPP or SEP)
• almost the same as SEC, missing plastic cartridge
cover
– Celerons above 300 MHz also found in Plastic
Pin Grid Array packages (PPGA)
• it is recommend to get a motherboard with a Slot 1
processor connection as you can install a PPGA using
an adapter but you cannot install SEC/SEP in a
motherboard with a Socket PGA-370 connection

30. Sixth-Generation (P6)
• 7.5 million transistors in 300 MHz and below
• 19 million transistors above 300-A MHz
SPEED
233 MHz
266 MHz
300 MHz
300-A MHz
333 MHz
366 MHz
400 MHz
433 MHz
466 MHz
L2 Cache
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Package
SEP
SEP
SEP
SEP, PPGA
SEP, PPGA
SEP, PPGA
SEP, PPGA
SEP, PPGA
PPGA

31. Sixth-Generation (P6)
Pentium III
– P6 with SSE
• 70 new instructions
• improve on advanced imaging, 3D, streaming audio, video,
speech-recognition
– 9.5 million transistors
– 512KB of half-core speed L2 cache
• can cache up to 4GB of addressable memory
– self-reportable processor serial number
– Most packaged in Single Edge Contact Cartridge 2
(SECC2)

32. Sixth-Generation (P6)

33. Processor Memory-Addressing Capabilities
Pentium III / II Xeon
– larger SEC package
– connects to motherboard via Slot 2

34. Other Sixth-Generation Processors
– Nexgen Nx586
• Not pin compatible with Pentiums
– normally soldered on motherboards
•
•
•
•
Had all fifth-generation features
Had sixth-generation feature of branch prediction
Had RISC core
Was discontinued after merger with AMD
– AMD-K6
• Competes with Pentium II
• Uses MMX technology
• In early tests, performed faster than Pentium II in normal
business applications

35. Processor Memory-Addressing Capabilities
AMD-K6
• Socket 7 interface
• Sixth-generation internal design, fifth-generation interface
– AMD-K6-2
• Higher clock speeds
• Higher bus speeds of up to 100MHz
• 3DNow; 21 new graphics and sound processing instructions
– AMD-K6-3
• 256KB of on-die full core speed L2 cache

36. Processor Memory-Addressing Capabilities
Motherboards must be able to support AMD voltages.
• Must have AMD-K6 processor ready BIOS
– AMD-K7 (Athlon)
• Cartridge type packaging, Slot A, not compatible with Pentium
II / III motherboards
• Speeds of 550 MHz and up
• 128KB L1 cache
• 512KB L2 cache, running at 1/2, 2/5, or 1/3 processor speed
depending model
• Athlon - Thunderbird has 256K on-processor cache
• does not support SSE instructions
– AMD Duron
• The same as the Athlon with a smaller L2 cache

37. Processor Memory-Addressing Capabilities
Cyrix MediaGX
• inexpensive
• soldered on motherboard
• do not need graphics or sound card - integrated into processor
and special motherboard
• more disposable than upgradable
• equivalent performance with Pentiums in the same speed range
• available at 166, 180 MHz, MMX-enhanced available in 200,
233MHz
• used in Compaq Presario 1220 notebooks

38. Processor Memory-Addressing Capabilities
Cyrix MX/MII
• compatible with MMX technology
• achieves higher performance and better value than competitive
processors
• not all motherboards can except this processor

39. Seventh-Generation Processors
Intel Pentium 4
•
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•
•
•
•
•
•
•
•
•
1.3Ghz -1.7Ghz and up
Forty-two million transistors
Software compatible with previous Intel processors
Processor front-side bus runs at 400Mhz
Arithmetic logic units run at twice the processor core frequency
20-stage pipeline
Very deep out-of-order instruction execution
Enhanced branch prediction
20KB L1 cache
L2 cache up to 4GB RAM, supports ECC
SSE2 instruction set, 144 new instructions
Enhanced floating-point unit
Multiple low-power states

40. Eighth-Generation Processor
Intel Itanium
• Designed primarily for servers
• 733 MHz and 800 MHz speeds
• Three levels of integrated cache
– 2 MB or 4 MB of on-cartridge L3 cache running at full-core speed
– 96 KB of L2 cache
– 32 KB of L1 cache
•
•
•
•
•
266 MHz, 64-bit wide CPU front-side bus with 2.1 GB/second bandwidth
25 million transistors
Sixteen TB physical memory addressing
Software compatible with previous versions
Explicitly parallel instruction computing (EPIC) technology-up to 20
operations per cycle

41. Processor Memory-Addressing Capabilities
Two integer and to memory units that can execute
four instructions per clock cycle
• Two floating-point multiply accumulate units with 82-bit
operands
• FMAC unit is capable of executing two floating-point
operations per clock
• Two additional MMX units
• Eight single-precision FP operations can be executed every
cycle
• 128 integer registers, 128 floating-point registers, 8 branch
registers, 64 predicate registers
• New cartridge type which includes processor and L3 cache
• Dedicated cartridge power connector

42. Processor Upgrades

43. PC Hardware Links -by Chris Hare
http://users.erols.com/chare/main.htm
for processor sockets:
http://users.erols.com/chare/sockets.htm

44. Processor Sockets
http://users.erols.com/chare/sockets.htm
• Various 486 Sockets - Socket 1, 2, 3, and 6.
http://support.intel.com/support/processors/overdrive/pentium/20284.ht
m
• Various Pentium Sockets - Socket 4, 5, 7, and 8.
http://support.intel.com/support/processors/overdrive/pentium/20236.ht
m

45. Pentium® 4 processors - Comparison Chart
http://www.intel.com/support/processors/pentium4/p4compare.htm

46. PC Hardware Links -by Chris Hare
http://users.erols.com/chare/main.htm
for processor sockets:
http://users.erols.com/chare/sockets.htm