MICROPROCESSOR
CPU stands for Central Processing Unit. Let us briefly
study that name:
•It is a processor, because it processes (moves and
calculates)
data
.
•It is central, because it is the center of PC data
processing.
•It is a unit, because it is a chip, which contains
millions of transistors.
MANUFACTURERS
IBM
CYRIX
INTEL CORPORATION
BUS
a typical processor has two important
buses for carrying data and
memory--addressing information
data bus
data bus
-the bundle of wires (or pins)
used to send and receive
data
The more signals that can be sent
at the same time, the more data can
be transmitted in a specified interval
and, therefore, the faster the bus.
HYBRID DESIGNS
Internal Registers
The size of the internal register is
a good indication of how much
information the processor can
operate on at one time.
internal data bus
386 to the Pentium--use 32-bit internal registers
386SX
32-bit IR
16-bit data bus
386DX
32-bit IR
32-bit data bus
80386
32-bit IR
64-bit data bus
Pentium
Address Bus
the set of wires that carry the
addressing information used to
describe the memory location to
which the data is being sent, or
from which the data is being retrieved.
The size (or width) of the address bus
indicates the maximum amount of RAM
that a chip can address.
The size of the data bus is an indication
of the information-moving capability
of the chip, and the size of the
address bus tells you how much
Intel Processor Memory-Addressing Capabilities
64 65,536 67,108,864 68,719,476,736 36-bit Pentium II 4 4,096 4,194,304 4,294,967,296 32-bit 386DX-Pentium Pro none 16 16,384 16,777,216 24-bit 286/386SX none 1 1,024 1,048,576 20-bit 8088/8086 Gbytes Mbyte s Kilobytes Bytes Address Bus Processor Family1 hertz = one cycle per second
The hertz was named for the German physicist
Heinrich Rudolph Hertz. In 1885, Hertz confirmed
through experimentation the electromagnetic
theory, which states that light is a form of
electromagnetic radiation and is propagated as wave
A single cycle is the smallest element of
time for the processor. Every action
requires at least one cycle and usually
multiple cycles. To transfer data to
and from memory, for example, an 8086
chip needs four cycles plus wait states.
A
wait state
is a clock tick in which
Nothing happens to ensure that
the processor isn't getting ahead of
the rest of the computer
A 286 needs only two cycles plus any
wait states for the same transfer.
AVERAGE CYCLES PER
INSTRUCTION
MICROPROCESSOR
1
Pentium
2
486
4.5
286 and 386
12
8086 and 8088
100MHz Pentium is about equal to
200MHz 486
400MHz 386 or 286
1,000MHz 8088
66 4.5x Pentium II 300 66 4x Pentium II 266 66 3.5x Pentium-MMX/Pentium II 233 66 3x Pentium/Pentium Pro/MMX 200 60 3x Pentium/Pentium Pro 180 66 2.5x Pentium/Pentium Pro/MMX 166 60 2.5x Pentium 150 66 2x Pentium 133 60 2x Pentium 120 66 1.5x Pentium 100 60 1.5x Pentium 90 50 1.5x Pentium 75 66 1x Pentium 66 60 1x Pentium 60 Motherboard Speed CPU Clock CPU Type/Speed
overclocking
Most of the processors running at 50MHz and
higher should have a heat sink installed
Microprocessor Progression: Intel
The following table helps you to understand the differences between the different processors that Intel has introduced over the years.
~7,000 32 bits 64-bit bus 3.6 GHz 0.09 125,000,000 2004 Pentium 4 "Prescott" ~1,700 32 bits 64-bit bus 1.5 GHz 0.18 42,000,000 2000 Pentium 4 ~510 32 bits 64-bit bus 450 MHz 0.25 9,500,000 1999 Pentium III ~300 32 bits 64-bit bus 233 MHz 0.35 7,500,000 1997 Pentium II 100 32 bits 64-bit bus 60 MHz 0.8 3,100,000 1993 Pentium 20 32 bits 25 MHz 1 1,200,000 1989 80486 5 32 bits 16 MHz 1.5 275,000 1985 80386 1 16 bits 6 MHz 1.5 134,000 1982 80286 0.33 16 bits 8-bit bus 5 MHz 3 29,000 1979 8088 0.64 8 bits 2 MHz 6 6,000 1974 8080 MIPS Data width Clock speed Microns Transistors Date Name
Transistors is the number of transistors on the chip. You can see that the number of transistors on a single chip has risen steadily over the years.
Microns is the width, in microns, of the smallest wire on the chip. For
comparison, a human hair is 100 microns thick. As the feature size on the chip goes down, the number of transistors rises.
Clock speed is the maximum rate that the chip can be clocked at. Clock speed will make more sense in the next section.
Data Width is the width of the ALU. An 8-bit ALU can
add/subtract/multiply/etc. two 8-bit numbers, while a 32-bit ALU can manipulate 32-bit numbers. An 8-bit ALU would have to execute four instructions to add two 32-bit numbers, while a 32-bit ALU can do it in one instruction. In many cases, the external data bus is the same width as the ALU, but not always. The 8088 had a 16-bit ALU and an 8-bit bus, while the modern Pentiums fetch data 64 bits at a time for their 32-bit ALUs.
MIPS stands for "millions of instructions per second" and is a rough measure of the performance of a CPU. Modern CPUs can do so many different things that MIPS ratings lose a lot of their meaning, but you can get a general sense of the relative power of the CPUs from this column.
Microprocessor History
A microprocessor -- also known as a CPU or central
processing unit -- is a complete computation engine that
is fabricated on a single chip. The first microprocessor
was the Intel 4004, introduced in 1971. The 4004 was not
very powerful -- all it could do was add and subtract, and
it could only do that 4
bits
at a time. But it was amazing
that everything was on one chip. Prior to the 4004,
engineers built computers either from collections of chips
or from discrete components (
transistors
wired one at a
time). The 4004 powered one of the first portable
The first microprocessor to make it into a
home computer was the Intel 8080, a
complete 8-bit computer on one chip,
introduced in 1974. The first microprocessor
to make a real splash in the market was the
Intel 8088, introduced in 1979 and incorporated into the IBM
PC (which first appeared around 1982). If you are familiar
with the PC market and its history, you know that the PC
market moved from the 8088 to the 80286 to the 80386 to
the 80486 to the Pentium to the Pentium II to the Pentium III
to the Pentium 4. All of these microprocessors are made by
Intel and all of them are improvements on the basic design of
the 8088. The Pentium 4 can execute any piece of code that
ran on the original 8088, but it does it about 5,000 times
640K conventional memory barrier
-Total of 1,024K (1mb) addressable location
-Upper portion reserved for adapter and system BIOS -Lower portion (640k for DOS and applications)
Intel 8088 and 8086
Microprocessor
8088 (1978)- operates at 4.77Mhz (about 4,770,000 ticks or heartbeats per second
- 8 bit data bus
- used on IBM PCs and XTs (Extended Technology)
8086 (1976)
- 16 bit data bus - costly
- increased instruction sets
- 80186 (full 16 bit)
- 80188 (8 bit)
- Both combined on a single chip 15 to 20
of the 8086-8088 series system components
(reduced number of components in
computer design)
- used for highly intelligent peripheral adapter
cards, such as network adapters
Intel 80186 and 80188
Microprocessor
Two modes of Operation Real-mode
- acts essentially the same as an 8086 chip and is fully object-code compatible with the 8086 and 8088
Protected Mode
- believed to have access to 1G of memory (including virtual memory)
-16Mb of actual addressable memory
- it cannot switch from protected mode to real mode without a hardware reset (a warm reboot)
- Intel's first attempt to produce a CPU chip that supported multitasking (Windows)
Intel 80286
Microprocessor
80286 processor - abbreviated as 286 - introduced in 1981- the CPU behind the IBM AT (Advance Technology)
-
introduced in 1985- offers greater performance in almost all areas of operation - a full 32-bit processor
- 386 can execute the real-mode instructions of an 8086 or 8088, but in fewer clock cycles
- additional software capability (modes) and a greatly enhanced Memory Management Unit (MMU).
- 386 can switch to and from protected mode under software control without a system reset
Virtual real mode (sometimes called virtual 86 mode)
- can run with hardware memory protection while simulating an 8086's real-mode operation
Intel 80386
386DX Processors
- full 32-bit processor - 32-bit internal registers - 32-bit internal data bus - 32-bit external data bus
- 275,000 transistors in a VLSI (Very Large Scale Integration) - 132-pin package
- less power requirement than 8086
- speed ranges form 16MHz to 33MHz; other manufacturers,
primarily AMD and Cyrix, offered comparable versions with speeds up to 40MHz
386SX Processors
- code named P9 chip
- 386 capability at the cost of 286 - 16-bit system
- can address only up to 16M of memory - speeds at 16 to 33 Mhz
- signaled the end of 286 processors
- 16MHz 386SX is not markedly faster than a 16MHz 286,
but it does offer improved memory-management capabilities
386SL Processors
- low-power CPU
- same capabilities as the 386SX
- designed for laptop systems in which low power
consumption is needed
- offer special power-management features (sleep modes) - chip includes an extended architecture that includes a
System Management Interrupt (SMI)
- the higher transistor count in the SL chips (855,000)
compared with even the 386DX processor (275,000
Four main features make a given 486 processor roughly twice as fast as an equivalent MHz 386 chip.
These features are:
- Reduced instruction-execution time
Instructions in the 486 take an average of only two
clock cycles to complete, compared with an average of more than four cycles on the 386.
Intel 80486
80486
- Internal (Level 1) cache
The built-in cache has a hit ratio of 90 to 95 percent, which describes how often zero-wait-state read operations will occur. External caches can improve this ratio further.
- Burst-mode memory cycles
A standard 32-bit (4-byte) memory transfer takes two clock cycles. After a standard 32-bit transfer, more data up to the next 12 bytes (or three transfers) can be transferred with only one cycle used for each 32-bit (4-byte) transfer. Thus, up to 16 bytes of contiguous, sequential memory data can be
transferred in as little as five cycles instead of eight cycles or more. This effect can be even greater when the transfers are only 8 bits or 16 bits each
80486
- Built-in (synchronous) enhanced math coprocessor (some
versions) (FPU – Floating-point unit)
The math co- processor runs synchronously with the main processor and executes math instructions in fewer
cycles than previous designs did. On average, the math coprocessor built into the DX-series chips provides two to three times greater math performance than an external 387 chip.
486 Processors
- about twice as fast as the 386
- easily be upgraded to a DX2 or DX4 processor - the 486 rapidly killed off the 386
- spawned the widespread acceptance of GUIs - speeds from 16MHz all the way up to 120MHz
Intel DX2 and DX4 Operating Speeds versus
Motherboard Clock Speeds
N/A 120MHz 100MHz 75MHz 60MHz 48MHz DX4 (3x mode) speed N/A 100MHz 83MHz 63MHz 50MHz 40MHz DX4 (2.5x mode) speed 100MHz 80MHz 66MHz 50MHz 40MHz 32MHz DX4 (2x mode) speed N/A 80MHz 66MHz 50MHz 40MHz 32MHz DX2 processor speed 50MHz 40MHz 33MHz 25MHz 20MHz 16MHz Motherboard Clock Speed
486DX Processors
- introduced on April 10, 1989
- Two main features
- Integration (math coprocessor,cache controller, cache memory)
- Upgradability (double-speed OverDrive)
- 32-bit internal register size - 32-bit external data bus - 32-bit address bus
- contains 1.2 million transistors on a piece of silicon no
larger than a thumbnail
486SL Processors
- SL Enhancement refers to a special design that
incorporates special power-saving features
- designed to be installed in laptop or notebook systems - eventually found their way into desktop systems
- incorporates System Management Mode (SMM) - suspend/resume
- designed to consume almost no power in the suspend
486SX Processors
- introduced in April 1991
- lower-cost version of the 486
- full DX processor, but the chip does not incorporate the
FPU
- had a completely different pinout
- twice as fast as a 386DX with the same clock speed
- normally available in 16, 20, 25, and 33MHz-rated speeds - SX/2 version up to 50 or 66MHz
487SX
( Math co-processor)
&
Built in
Pentium and thereafter
None
80486SX
Built in
80486DX
80387
80386
80287
80286
8087
8086
FPU
CPU
487 SX
- a complete 25MHz 486DX CPU with an extra pin added and
some other pins rearranged
- provides math coprocessor functionality in the system - prepared its real surprise: the OverDrive processor
- any system that supports the 487SX also supports the
DX2/OverDrive
DX2/OverDrive and DX4 Processors
- March 3, 1992, Intel introduced the DX2 speed-doubling
processors
- On May 26, 1992, DX2 processors were available in a retail
version called OverDrive
- Originally, the OverDrive versions of the DX2 were available
only in 169-pin versions, which meant that they could be used only with 486SX systems that had sockets configured to support the rearranged pin configuration
- On September 14, 1992, Intel introduced 168-pin OverDrive
versions for upgrading 486DX systems.
- DX2/OverDrive processors run internally at twice the clock
rate of the host system
- DX2 chip that doesn't run at double speed is the bus
Table 6.6 Intel 486/Pentium CPU Socket Types and Specifications Pentium Pro VRM dual-pattern SPGA 387 Socket 8 Pentium 75-200, Pentium 75+ OverDrive VRM 37x37 SPGA 321 Socket 7 DX4, 486 Pentium OverDrive 3.3v 19x19 PGA 235 Socket 6 Pentium 75-133, Pentium 75+ OverDrive 3.3v 37x37 SPGA 320 Socket 5 Pentium 60/66, Pentium 60/66 OverDrive 5v 21x21 PGA 273 Socket 4 SX/SX2, DX/DX2, DX4, 486 Pentium OverDrive 5v/3.3v 19x19 PGA 237 Socket 3 SX/SX2, DX/DX2*, DX4
OverDrive, 486 Pentium OverDrive 5v 19x19 PGA 238 Socket 2 SX/SX2, DX/DX2*, DX4 OverDrive 5v 17x17 PGA 169 Socket 1 Supported Processors Voltage Pin Layout No. of Pins Socket Number
Active Socket 5/7
Pentium 75/90/100 Pentium OverDrive with
MMX Active Socket 4 Pentium 60/66 60/66 Pentium OverDrive Active Socket 2 or 3 486SX/DX/SX2/DX 2 486 Pentium OverDrive Heat Sink Socket Replaces Processor Designation
OverDrive Compatibility Problems
Although you can upgrade many older 486SX or 486DX systems with the OverDrive processors, some exceptions exist.
Four factors can make an OverDrive upgrade difficult or impossible:
- BIOS routines that use CPU-dependent timing loops
- Lack of clearance for the OverDrive heat sink (25MHz
and faster)
- Inadequate system cooling
- October 19, 1992, Intel announced P5 (Pentium) processor - shipped on March 22, 1993
- features twin data pipelines (superscalar technology )
u-pipe (primary pipe)- execute all integer and floating-point instructions
v-pipe (secondary pipe) - execute only simple integer instructions and certain floating-point instructions
pairing - operating on two instructions simultaneously in the different pipes
- one of the first CISC (Complex Instruction Set Computer)
chips
- Branch Target Buffer (BTB) that employs a technique called
branch prediction
- SL enhanced (incorporate the SMM) - Built-in FPU
Pentium Processor Specifications
5v (first generation), 3.465v, 3.3v, 3.1v, 2.9v (second generation) Operating voltage:
SMM (System Management Mode), enhanced in second generation Power management:
Built-in FPU (Floating-Point Unit) Math coprocessor:
273-pin PGA, 296-pin SPGA, Tape Carrier External package:
0.8 micron (60/66MHz), 0.6 micron (75-100MHz), 0.35 micron (120MHz and up) Circuit size: 3.1 million Number of transistors: Yes Burst-mode transfers:
Two-Way Set Associative, Write-Back Data Integral-cache type: 8K code, 8K data Integral-cache size: 4G Maximum memory: 32-bit Memory address bus: 64-bit External data bus:
32-bit Register size:
1x (first generation), 1.5x-3x (second generation) CPU clock multiplier:
60, 66MHz (first generation); 75, 90, 100, 120, 133, 150, 166, 200MHz (second generation)
Maximum rated speeds:
March 22, 1993 (first generation); March 7, 1994 (second generation) Introduced:
First Generation Pentium
- 60 and 66MHz processor speeds
- 273-pin PGA form factor and ran on 5v power
- ran at the same speed as the motherboard(1x clock) - 0.8-micron BiCMOS process
Second Generation Pentium
- March 7, 1994
- 75, 90 and 100MHz versions
- Eventually, 120, 133, 150, 166, and 200MHz versions were
also introduced
- 0.6-micron (75/90/100MHz) BiCMOS technology - 120 and higher MHz second-generation versions
incorporate an even smaller die built on a 0.35-micron
Second Generation Pentium
- come in a 296-pin SPGA (Staggered Pin Grid Array)
- physically incompatible with the first-generation versions - 3.3 million transistors
for additional clock-control SL enhancements
on-chip Advanced Programmable Interrupt Controller dual-processor interface (Symmetric Multi-Processing ) - use clock-multiplier circuitry
66 3x Pentium 200 66 2.5x Pentium 166 60 2.5x Pentium 150 66 2x Pentium 133 60 2x Pentium 120 66 1.5x Pentium 100 60 1.5x Pentium 90 50 1.5x Pentium 75
Memory Bus Speed CPU Clock
Pentium-MMX Processor
Third Generation Pentium (MMX)
- code-named P55C
- released in January 1997
- incorporates what Intel calls MMX technology
- clock rates of 66/166MHz, 66/200MHz, and 66/233MHz
- include superscalar architecture, multi-processor support, on-chip local APIC controller, and power management features
- New features include a pipelined MMX unit, 16K code and Write-Back cache
- 4.5 million transistors
- produced on an enhanced 0.35-micron CMOS silicon process which allows for a lower 2.8v voltage level
- Socket 7 with VRM (321-pin processor socket)
- MMX incorporates a process Intel calls Single Instruction Multiple Data
(SIMD)
- 57 new instructions (specifically to handle video, audio, and graphics data )
Pentium Pro
Fourth Generation (Pentium Pro)
- introduced in September of 1995
- 387-pin unit that resides in Socket 8
- Multi-Chip Module (MCM) physical format (Dual Cavity PGA
(Pin Grid Array) package )
- 36.5 million transistors
Processor Die contains 5.5 million transistors 256K cache die contains 15.5 million transistors 512K cache die has 31 million transistors
- includes three internal instruction pipes - Built-in L2 cache
- MPS allows configurations of up to four processors running
Pentium Pro Processor Specifications
3.3v Operating voltage:
SMM (System Management Mode) Power management:
Built-in FPU (Floating-Point Unit) Math coprocessor:
387-pin Dual Cavity PGA (Pin Grid Array) External package:
0.35 micron Circuit size:
15.5 million (256K cache), 31 million (512K cache) Transistors in L2 cache: 5.5 million Number of transistors: non-blocking, L1 cache Integral-cache type: 8K code, 8K data Integral-cache size: 4G Maximum memory: 32-bit Memory address bus:
64-bit Integrated-cache bus:
64-bit External data bus:
32-bit Register size:
2.5x-3x CPU clock multiplier:
150, 166, 180, 200MHz Maximum rated speeds:
September 1995 Introduced:
Pentium II
- code name "Klamath - May 1997
- Single Edge Contact (SEC) cartridge
- Pentium II 266MHz chip is more than twice as fast as a
classic Pentium 200MHz
- a Pentium Pro with MMX technology instructions - 0.35 micron
- incorporates Dual Independent Bus architecture (one for
accessing the L2 cache, the other for accessing main memory )
66 5x Pentium II 333 66 4.5x Pentium II 300 66 4x Pentium II 266 66 3.5x Pentium II 233 Motherboard Speed CPU Clock CPU Type/Speed
2.8v Operating voltage:
SMM (System Management Mode) Power management:
Built-in FPU (Floating-Point Unit) Math coprocessor:
242-pin Single Edge Cartridge External package: 0.35 micron Circuit size: 31 million Transistors in L2 cache: 512K L2 cache size: 7.5 million Number of transistors: non-blocking, L1 cache Integral-cache type: 16K code, 16K data Integral-cache size: 64G Maximum memory: 32-bit Memory address bus:
64-bit Integrated-cache bus:
64-bit External data bus:
300-bit Internal bus width:
3.5x,4x-4.5x CPU clock multiplier:
233, 266, 300MHz Maximum rated speeds:
May 1997 Introduced:
Performance Headroom for the Applications You Need
Whether you're into media, PC imaging, or communications, the Pentium II processor has plenty of special product features to meet your needs:
100MHz Front Side Bus (available with 450MHz, 400MHz and 350MHz) Dual Independent Bus architecture (D.I.B.)
Dynamic Execution
Intel MMX™ technology
Single Edge Contact Cartridge (S.E.C.C.)
In fact the Pentium III contained two rather different news items,
one small and one somewhat bigger. Intel's new top processor
is a Pentium II in principle. It is mounted in a BX based
motherboard with Slot 1. This processor has some built-in
features:
A rather problematic ID numbering.
New registers and 70 new instructions.
Finally the clock speed was raised to 500 MHz with room for
further increases. Pentium III Xeon (code name Tanner) was
introduced March 17th, 1999. It was a Xeon chip updated with
all the new features from Pentium III. To utilize it Intel has the
840 chipset.
-System scalability up to 64 GB
- 400 MHz Front Side Bus of 128 bit width - 20 KB L1 cache and 256 KB L2
- The ALU (Arithmetical Logic Unit) runs at twice the clock speed
- Intel® MMX™ media enhancement technology
- Internet Streaming SIMD Extensions
- Compatible with Intel® Architecture-based software
- 0.13 or 0.18 micron technology
- Intel® NetBurst™ micro-architecture
- PGA-423 and mPGA-478 form factors
- Speeds up to 2.20 GHz
- A new socket for simple motherboard design - Clock frequencies from 1500 MHz
- 20 stages pipeline
- SSE2 and 128 bit MMX - 42 millions of transistors
- A new 423 pins socket design
- Dual Rambus memory channel with i850 chipset - Only single processor mode available.
NetBURST
Intel uses the term NetBURST to describe some features in Pentium 4:
Advanced Dynamic Execution The Rapid Execution Engine
Advanced Dynamic Execution means that the processor may execute up to 6
instructions simultanously.
Using Rapid Execution Engine certain instructions may be executed at twice the normal speed.
A 'Willamette' core Pentium 4.
“Willamette”
•1.4 and 1.5 GHz
•released in November 2000
•Socket 423 , later revisions moving to socket 478
•100 MHz Quad-pumped (400Mhz FSB)
•sacrificed per-cycle performance in order to gain two things: very high clockspeeds, and SSE performance
•also comes in a low-end Celeron version (often referred to as Celeron 4) and a high-end Xeon version intended for SMP configurations.
A 'Northwood' core Pentium 4 processor (P4A) •2.0 , 2.2 , 2.4, 2.8 GHz
•3.06 GHz processor supported Hyper-threading (800FSB) •400 MHz to 533 MHz FSB
•released in January 2002
•combined an increase in the secondary cache size from 256k to 512k •0.13 micron or 130nm)
•socket 478 (socket 423 with adapters)
•3.2 GHz variant was launched in June and a final 3.4 GHz version wa launched in early 2004
Pentium 4 Extreme Edition (P4EE)
•2 MB of Level 3 cache
•Socket 478 form factor , LGA775 version is also available
•In office applications, the Extreme Edition was generally a bit slower than the Northwood
•Some games benefited from the added cache, particularly those based on the Quake III and Unreal engines
•improved most in multimedia encoding •bus speed from 800 MHz to 1066MHz
•Only one Gallatin-based chip at 3.46 GHz was released before the Extreme Edition was migrated to the Prescott core
Prescott
•90nm process
•clocked at the same rate as a Northwood
•benchmarks show that a Northwood runs slightly faster than a Prescott •Currently, 3.8 GHz is the fastest Prescott-based processor
•from Socket 478 to LGA775
•LGA775 reference cooler and mounting system were somewhat better designs •thermal problems were so severe
•Intel decided to abandon the Prescott architecture altogether, and attempts to roll out a 4 GHz
•showed in extreme cases it took a 5.2 GHz Prescott core to match the performance of an Athlon FX-55 that clocked at 2.6 GHz
•marketed as the
Pentium D
8xx
•reputed to have a 60-80% increase in performance per clock-speed •launched May 2005
•Dubbed the “
Smithfield
” core •two connected Prescott cores22,000,000 37,000,000 42,000,000 1999 2000 2001 AMD original Athlon
AMD Athlon Thunderbird Pentium 4 7th. Generation 27,400,000 18,900,000 9,300,000 ? 28,000,000 1999 Mobile Pentium II Mobile Celeron Pentium III AMD K6-3 Pentium III CuMine Improved 6th. Generation 5,500,000 8,800,000 7,500,000 9,300,000 1995 1997 1997 1998 Pentium Pro AMD K6 Pentium II AMD K6-2 6th. Generation 4,500,000 6,000,000 6,000,000 1997 1997 1998 Pentium MMX IBM/Cyrix 6x86MX IDT WinChip2 3D Improved 5th. Generation 3,100,000 -- -- 3,500,000 1993-95 1996 1996 1997 Pentium Cyrix 6X86 AMD K5 IDT WinChip C6 5th. Generation 1,200,000 1990-92 80486SX, 80486DX, 80486DX2 and 80486DX4 4th. Generation 275,000 1987-88 80386DX and 80386SX 3rd. Generation 134,000 1984 80286 2nd. Generation 29,000 1978-81 8086 and 8088 1st. Generation Number of transistors Year CPUs PC
