Since there are a lot of questions about the differences between the various
CPU's, this list has been compiled for the benefit of the net community.
I hope it can answer some questions.

This list is the result of collecting many snippets of information from
Usenet. Although this is the second release, it will probably still contain
some bugs. Any corrections, additions, or comments are welcome. 

I will try to incorporate all replies in a next release. If there is enough
interest, regularly posted new releases are a possibility.

Contents:

1 CPU
1.1 Manufacturers
1.1.1 Intel
1.1.2 AMD
1.1.3 IBM
1.1.4 Chips & Technologies
1.1.5 Cyrix
1.1.6 Texas Instruments
1.2 Intel i4004 CPU
1.3 Intel i4040 CPU
1.4 Intel i8008 CPU
1.5 Intel i8080 CPU
1.6 Intel i8085 CPU
1.7 Intel i8086/i8088 CPU
1.7.1 Intel i8086 CPU
1.7.2 Intel i8088 CPU
1.8 Intel i80186/i80188 CPU
1.8.1 Intel i80186 CPU
1.8.2 Intel i80C186 CPU
1.8.3 Intel i80188 CPU
1.9 NEC V30/V20 CPU
1.9.1 NEC V30 CPU
1.9.2 NEC V20 CPU
1.10 Intel i80886 CPU
1.11 Intel i80286 CPU
1.12 Harris 80286 CPU
1.13 Intel i80386 CPU
1.13.1 Intel i80386/i80386DX CPU
1.13.2 Intel i80386SX CPU
1.13.3 Intel i80386SL CPU
1.13.4 Intel RapidCAD CPU
1.13.5 Intel i386SX microprocessor
1.13.6 Intel i386CX microprocessor
1.13.7 Intel i386EX microprocessor
1.14 AMD Am386 CPU
1.14.1 AMD Am386DX CPU
1.14.2 AMD Am386DXL CPU
1.14.3 AMD Am386DXLV CPU
1.14.4 AMD Am386SX CPU
1.14.5 AMD Am386SXL CPU
1.15 IBM 386 CPU
1.15.1 IBM 386SLC CPU features
1.16 Chips & Technologies 386 CPU
1.16.1 Chips & Technologies Super386 38600DX CPU
1.16.2 Chips & Technologies 38605DX CPU
1.16.3 Chips & Technologies 38600SX CPU
1.17 IBM 386/486 hybrid CPU
1.17.1 IBM 486DLC CPU
1.17.2 IBM 486DLC2 CPU
1.17.3 IBM 486BLX2 CPU (Blue Lightening)
1.17.4 IBM 486BLX3 CPU (Blue Lightening)
1.17.5 IBM 486SLC CPU
1.17.6 IBM 486SLC2 CPU
1.18 Cyrix 386/486 hybrid CPU
1.18.1 Cyrix Cx486DLC CPU
1.18.2 Cyrix Cx486SLC CPU
1.18.3 Cyrix Cx486DLC / Cx486SLC CPU incompatibilities
1.18.4 Cyrix Cx486DRu2 CPU
1.18.5 Cyrix Cx486DRx2 CPU
1.18.6 Cyrix Cx486SRx2 CPU
1.19 Texas Instruments 386/486 hybrid CPU
1.19.1 Texas Instruments TI486DLC CPU
1.19.2 Texas Instruments TI486SLC CPU
1.19.3 Texas Instruments TI486SXLC2 CPU (Potomac)
1.19.4 Texas Instruments 386/486 hybrid CPU announcements
1.20 Intel i80486 CPU
1.20.1 Intel i80486DX CPU
1.20.2 Intel i80486SL CPU
1.20.3 Intel i80486DXL CPU
1.20.4 Intel i80486SX CPU
1.20.5 Intel i80486SXL CPU
1.20.6 Intel i80486DX2 CPU
1.20.7 Intel i80486DX3 CPU (announced)
1.20.8 Intel i80486 CPU announcements
1.21 AMD Am486 CPU
1.21.1 AMD Am486DX CPU
1.21.2 AMD Am486DXLV CPU
1.21.3 AMD Am486DX2 CPU
1.21.4 AMD Am486DX3 CPU (announced)
1.21.5 AMD Am486SX CPU
1.21.6 AMD Am486SX2 CPU
1.21.7 AMD Am486 CPU announcements
1.22 IBM 80486 CPU
1.22.1 IBM 80486DX CPU
1.22.2 IBM 80486SX CPU
1.23 Cyrix Cx486 CPU
1.23.1 Cyrix FasCache Cx486D CPU
1.23.2 Cyrix FasCache Cx486S CPU
1.24 Texas Instruments TI486 CPU
1.24.1 Texas Instruments TI486SXL2 CPU (Potomac)
1.25 Intel Overdrive CPU for Intel i80486 CPU
1.25.1 Intel i80486DX2 CPU for Intel i80486DX CPU (ODPR)
1.25.2 Intel i80486DX2 CPU for Intel i80486SX CPU (ODPR)
1.25.3 Intel i80486DX2 CPU for Intel i80486DX CPU or Intel i80486SX CPU
(ODP)
1.26 Intel Pentium CPU
1.26.1 Intel P54C CPU
1.26.2 Intel Pentium CPU announcements
1.27 Intel Overdrive CPU for Intel Pentium CPU
1.27.1 Intel P54M CPU
1.28 VESA Local Bus (VLB)


2 NPX
2.1 Intel i8087 NPX
2.2 Intel i80287 NPX
2.3 AMD Am80287 NPX
2.3.1 AMD Am80C287 NPX
2.3.2 AMD Am80EC287 NPX
2.4 Cyrix Cx287 NPX
2.5 Intel i80187 NPX
2.6 Intel i80287XL NPX
2.7 Cyrix Cx82S87 NPX
2.8 IIT IIT-2C87 NPX
2.9 Intel i80387 NPX
2.9.1 Intel i80387 NPX
2.9.2 Intel i80387DX NPX
2.9.3 Intel i80387SX NPX
2.9.4 Intel i80387SL NPX
2.10 Chips & Technologies 38700 NPX
2.10.1 Chips & Technologies 38700DX NPX
2.10.2 Chips & Technologies 38700SX NPX
2.11 Cyrix Cx80387 NPX
2.11.1 Cyrix FasMath Cx83D87 NPX
2.11.2 Cyrix FasMath Cx387+ NPX
2.11.3 Cyrix FasMath EMC87 NPX
2.11.4 Cyrix FasMath Cx83S87 NPX
2.11.5 Cyrix Cx387DX NPX
2.11.6 Cyrix Cx387SX NPX
2.12 IIT IIT-3C87 NPX
2.12.1 IIT IIT-3C87 NPX
2.12.2 IIT IIT-3C87SX NPX
2.13 ULSI Math*Co 83C87 NPX
2.14 ULSI Math*Co 83S87 NPX
2.15 Weitek Abacus 1167 NPX
2.16 Weitek Abacus 3167 NPX
2.17 Cyrix Cx487DLC NPX
2.18 Intel i80487 NPX
2.18.1 Intel i80487SX NPX
2.18.2 Intel i80487 NPX
2.19 Weitek Abacus 4167 NPX




1 CPU

1.1 Manufacturers

1.1.1 Intel

Intel makes the base models: i8086/8088, i80286, i80386, i80486, Pentium,
i8087, i80287, i80387.


1.1.2 AMD

AMD holds a second source license which dates back to the 8086. In the early
days mainframe companies had a rule that no chip would be used in a design,
unless it could be bought from at least two companies.

AMD invented a CMOS process that was faster than Intel's and vendors started
using them as a primary source.


1.1.3 IBM

IBM's licensing arrangements with Intel preclude them from selling their CPU's
directly. They can only sell these CPU's as long as they are sold with a
minimum amount of 'added value'.


1.1.4 Chips & Technologies


1.1.5 Cyrix

Cyrix implemented the chips they wanted to manufacture from the specifications
of the originals. They had Texas Instruments produce these chips for them.


1.1.6 Texas Instruments

Texas Instruments used to be Cyrix's major producer (SGS-Thompson was the
other one). Recently, Texas Instruments stopped producing chips for Cyrix and
now make their own chips under license from Cyrix.


1.2 Intel i4004 CPU

4 bit data bus.
12 bit address bus (multiplexed).

1971.

2300 transistors.


1.3 Intel i4040 CPU

Intel i4004 CPU with extra features: more instructions,
interrupt support.

4 bit data bus.
12 bit address bus (multiplexed).

1972.


1.4 Intel i8008 CPU

8 bit data bus.
16 bit address bus.

1972.


1.5 Intel i8080 CPU

8 bit data bus.
16 bit address bus.

1973.

5E3 transistors.


1.6 Intel i8085 CPU

8 bit data bus.
16 bit address bus.


1.7 Intel i8086/i8088 CPU

1 Mbyte address space, 64 kbyte per segment.


1.7.1 Intel i8086 CPU

16 bit internal data bus.
16 bit external data bus.
20 bit address bus.
Data and address bus are multiplexed.

1978.

4 MHz.
5 MHz.
8 MHz.
10 MHz.
12 Mhz.

Used in IBM PC clones, IBM PC/XT clones.

29E3 transistors.


1.7.2 Intel i8088 CPU

16 bit internal data bus.
8 bit external data bus (can co-operate with all Intel i8085 CPU
periphery chips).
20 bit address bus.
Data and address bus are multiplexed.

1979.

5 MHz.
8 MHz.
10 MHz.
12 MHz.

Used in IBM PC, IBM PC/XT.


1.8 Intel i80186/i80188 CPU

Intel i8086/i8088 CPU with extra features:
DMA,
timers,
extra instructions: all of the Intel i80286 CPU real mode instructions.


1.8.1 Intel i80186 CPU

16 bit internal data bus.
16 bit external data bus.
20 bit address bus.

1983.

6 MHz.
8 MHz.

Technology: NMOS.


1.8.2 Intel i80C186 CPU

Embedded version of Intel i80186 CPU.

16 MHz.

Technology: CMOS.


1.8.3 Intel i80188 CPU

16 bit internal data bus.
8 bit external data bus (can co-operate with all Intel i8085 CPU
periphery chips).
20 bit address bus.

1983.

6 MHz.
8 MHz.

Technology: NMOS.


1.9 NEC V30/V20 CPU

Intel i80186/i80188 CPU upward instruction compatible.
Extra features: extra instructions: BCD,
Intel i8080 CPU simulation,
fewer CPI (Cycles Per Instruction).


1.9.1 NEC V30 CPU

Intel i8086 CPU pin compatible.

10 MHz: $10.


1.9.2 NEC V20 CPU

Intel i8088 CPU pin compatible.

10 MHz: $10.


1.10 Intel i80886 CPU


1.11 Intel i80286 CPU

Real mode: Intel i8086/i8088 CPU mode.
Protected mode: 16 MByte address space, 64 kbyte per segment,
1 Gbyte virtual memory.

16 bit data bus.
24 bit address bus.

1982.

6 MHz.
8 MHz, PLCC (Plastic Leaded Chip Carrier), $4.
10 MHz, PLCC (Plastic Leaded Chip Carrier), $8.
12 MHz, PLCC (Plastic Leaded Chip Carrier), $6.
16 MHz, PLCC (Plastic Leaded Chip Carrier), $9.
20 MHz.

Used in IBM PC/AT.

134E3 transistors.


1.12 Harris 80286 CPU

Intel i80286 CPU instruction/pin compatible.

25 MHz.


1.13 Intel i80386 CPU

Real mode: Intel i8086/i8088 CPU mode.
Protected mode: 64 Tbyte virtual memory, 4 Gbyte per segment.
Virtual 8086 mode (V86 mode): parallel simulation of more virtual
Intel i8086/i8088 CPU's.

POPAD bug: EAX register is trashed when there is a memory access instruction
direct after the POPAD instruction.


1.13.1 Intel i80386/i80386DX CPU

32 bit internal data bus.
32 bit external data bus.
32 bit address bus.

1985.

12 MHz (First 16 MHz CPU's had clock speed troubles and were released as
12 MHz items).
16 MHz: early chips had a bug in the 32 bit MUL instruction (MUL bug).
20 MHz: $29.
25 MHz: $29.
33 MHz: $39, 2000 mW.

132 pin PGA (Pin Grid Array) package.

275E3 transistors.


1.13.2 Intel i80386SX CPU

32 bit internal data bus.
16 bit external data bus.
24 bit address bus.

16 MHz: $18.
20 MHz: $27.
25 MHz: $30.


1.13.3 Intel i80386SL CPU

Low power version of the Intel i80386SX CPU.
Extra pins assigned for power management.

Intel i80386SX CPU upward pin compatible.

25 MHz.
33 MHz.


1.13.4 Intel RapidCAD CPU

Intel i80386 CPU with FPU (same implementation as Intel i80486DX CPU).

The Intel RapidCAD CPU consists of a set of 2 chips. The Intel RapidCAD-1
(132 pin PGA) contains the Intel i80386 CPU with FPU. The Intel RapidCAD-2
(68 pin PGA) fits in the Intel i80387DX NPX socket and contains a PLA for the
FERR signal generation.

Intel i80386DX CPU / Intel i80387DX NPX pin compatible.

1992.

25 MHz.
33 MHz: $239, 3500 mW.


1.13.5 Intel i386SX microprocessor

Embedded version of Intel i80386SX CPU.
Static core.

24 bit address bus.

Packaging: 100 pin PQFP (Plastic Quad Flat Package),
die,
military.

16 MHz: 5 V, 0-16 MHz, 1993, $26.
20 MHz: 5 V, 0-20 MHz, 1993, $26.
25 MHz: 5 V, 0-25 MHz, 1993, $26.


1.13.6 Intel i386CX microprocessor

Embedded version of Intel i80386SX CPU.
Static core.

SMM (System Management Mode): system & power management: idle, powerdown,
powersave.

26 bit address bus.

Packaging: 100 pin PQFP (Plastic Quad Flat Package),
100 pin SQFP,
die,
military.

12 MHz: 3 V, 0-12 MHz, 1993, $27.
20 MHz: 3.3 V, 0-20 MHz, 1993, $27.
25 MHz: 5 V, 0-25 MHz, 1993, $27.


1.13.7 Intel i386EX microprocessor

Embedded version of Intel i80386SX CPU.
Static core.

SMM (System Management Mode): system & power management: idle, powerdown,
powersave.

26 bit address bus.

Packaging: 132 pin PQFP (Plastic Quad Flat Package),
144 pin SQFP,
die,
military.

16 MHz: 3 V, 0-16 MHz, 1994, $39.
20 MHz: 3.3 V, 0-20 MHz, 1994, $39.
25 MHz: 5 V, 0-25 MHz, 1994, $39.


1.14 AMD Am386 CPU

Intel i80386 CPU instruction/pin compatible.
Same core and microcode as Intel i80386 CPU.


1.14.1 AMD Am386DX CPU

Low power.

Intel i80386DX CPU pin/instruction compatible.

16 MHz: 2-16 MHz.
20 MHz: 2-20 MHz.
25 MHz: 2-25 MHz.
33 MHz: 2-33 Mhz.
40 MHz: 2-40 MHz, $59.


1.14.2 AMD Am386DXL CPU

Low power version of AMD Am386DX CPU.

40 MHz.


1.14.3 AMD Am386DXLV CPU

Low power, low voltage (3.3 V) version of AMD Am386DX CPU.


1.14.4 AMD Am386SX CPU

Low power.
Extra pins assigned for power management.

Intel i80386SX CPU upward pin compatible.

16 MHz: 2-16 MHz.
20 MHz: 2-20 MHz.
25 MHz: 2-25 MHz, $30.
33 MHz: 2-33 MHz.
40 MHz: 2-40 MHz.


1.14.5 AMD Am386SXL CPU

Low power version of AMD Am386SX CPU.

33 MHz: 0-33 MHz.


1.15 IBM 386 CPU

Intel i80386 CPU instruction compatible
Some instructions are executed faster than when executed by the
Intel i80386 CPU.


1.15.1 IBM 386SLC CPU features

Low power.
Extra pins assigned for power management.

8 kbyte cache.
To be enabled via software.

Intel i80386SX CPU upward pin compatible.


1.16 Chips & Technologies 386 CPU

Intel i80386 CPU instruction compatible, including undocumented
LOADALL386 instruction.
Own microcode (clean room).
Some instructions are executed faster than when executed by the
Intel i80386 CPU.


1.16.1 Chips & Technologies Super386 38600DX CPU

Intel i80386DX CPU pin compatible.

Co-operation with an appropriate NPX causes communication problems, which
cause the over-all performance to drop below that of an Intel i80386DX CPU
with NPX.

33 MHz: $80.
40 MHz: 1650 mW.

No longer available.


1.16.2 Chips & Technologies 38605DX CPU

512 byte instruction cache.

32 bit internal data bus.
32 bit external data bus.
32 bit address bus.
Not Intel i80386DX CPU pin compatible.

144 pin PGA.

No longer available.


1.16.3 Chips & Technologies 38600SX CPU

Intel i80386SX CPU pin compatible.

Never released.


1.17 IBM 386/486 hybrid CPU

Intel i80486 CPU instruction compatible, no FPU.
Intel i80386 CPU bus interface.


1.17.1 IBM 486DLC CPU

Intel i80386 CPU core, enhanced by IBM.

16 kbyte cache: 4-way set associative.
To be enabled via software.

32 bit internal data bus.
32 bit external data bus.
32 bit address bus.
Not Intel i80386DX CPU pin compatible.


1.17.2 IBM 486DLC2 CPU

Clock doubled version of the IBM 486DLC CPU.

Intel i80386 CPU core, enhanced by IBM.

16 kbyte cache: 4-way set associative.
To be enabled via software.

Intel i80386DX CPU pin compatible.


1.17.3 IBM 486BLX2 CPU (Blue Lightening)

Clock doubled version of the IBM 486DLC CPU.

Intel i80486 CPU core and microcode.

16 kbyte cache: 4-way set associative.
To be enabled via software.

Low power.
Power management.

Intel i80386DX CPU upward pin compatible.

25/50 MHz: 1993.
33/66 MHz: 1993.


1.17.4 IBM 486BLX3 CPU (Blue Lightening)

Clock tripled version of the IBM 486DLC CPU.

Intel i80486 CPU core and microcode.

16 kbyte cache: 4-way set associative.
To be enabled via software.

Low power.
Power management.

Intel i80386DX CPU upward pin compatible.

25/75 MHz: 1993.
33/99 MHz: 1993.


1.17.5 IBM 486SLC CPU

Intel i80386 CPU core, enhanced by IBM.

16 kbyte cache: 4-way set associative.
To be enabled via software.

32 bit internal data bus.
16 bit external data bus.
24 bit address bus.
Not Intel i80386SX CPU pin compatible.


1.17.6 IBM 486SLC2 CPU

Clock doubled version of the IBM 486SLC CPU.

Intel i80386 CPU core, enhanced by IBM.

16 kbyte cache: 4-way set associative.
To be enabled via software.

Intel i80386SX CPU pin compatible.

33/66 MHz, 1993.
40/80 MHz, 1993.


1.18 Cyrix 386/486 hybrid CPU

Intel i80486 CPU instruction compatible, no FPU.
Own core (clean room): not 100% compatible.
Intel i80386 CPU bus interface.


1.18.1 Cyrix Cx486DLC CPU

First generation 40 MHz CPU's had a bug: using a NPX (Cyrix EMC87 NPX,
Cyrix Cx83D87 NPX (until nov. 1991), IIT IIT-3C87 NPX) caused crashes. These
are caused by synchronisation errors in FSAVE and FSTOR instructions. Later,
improved CPU's have an AB prefix printed in the lower right corner. The
Cyrix 387+ NPX (European name for Cyrix Cx83D87 NPX from nov. 1991) causes
no trouble when co-operating with a bad Cyrix Cx486DLC CPU.

1 kbyte unified cache: write-through, direct-mapped / 2-way set-associative,
maximum of 4 non-cachable areas.
Hit rate: 65% without support of cache by motherboard, because of flush at
DMA,
85% with support of cache by motherboard (Cache Coherency Support).
To be enabled via software (BIOS).

32 bit internal data bus.
32 bit external data bus.
32 bit address bus.
Intel i80386DX CPU upward pin compatible.

25 MHz: $55.
33 MHz: $69.
40 MHz: $89, 2800 mW.

Clock Skewing Correction Circuit.

Contains a fast extra 16x16 bit multiplier.

Extra pins assigned for cache, power and A20 management:
cache management: KEN#,
FLUSH#,
RPLSET#,
RPLVAL#,
power management: SUSP#,
SUSPA#,
A20 management: A20M#.


1.18.2 Cyrix Cx486SLC CPU

1 kbyte unified cache: write-through, direct-mapped / 2-way set-associative,
maximum of 4 non-cachable areas.
hit rate: 65% without support of cache by motherboard, because of flush at
DMA,
85% with support of cache by motherboard (Cache Coherency Support).
To be enabled via software (BIOS).

32 bit internal data bus.
16 bit external data bus.
24 bit address bus.
Intel i80386SX CPU upward pin compatible.

25 MHz: $128.
33 MHz: $159.
40 MHz.

Clock Skewing Correction Circuit.

Contains a fast extra 16x16 bit multiplier.

Extra pins assigned for cache, power and A20 management:
cache management: KEN#,
FLUSH#,
RPLSET#,
RPLVAL#,
power management: SUSP#,
SUSPA#,
A20 management: A20M#.


1.18.3 Cyrix Cx486DLC / Cx486SLC CPU incompatibilities

Same registers.
Same instruction set.
Differences in execution time of various instructions, average CPI (Cycles
Per Instruction) about equal.

Crashes with: NextStep,
DBOS 1.0 DOS extender of Salford FTN/386,
Fortran compiler.


1.18.4 Cyrix Cx486DRu2 CPU

Direct Replacement Unit.
'Clock doubled' version of the Cyrix Cx486DLC CPU.
In fact a Cyrix Cx486DLC CPU with some additional hardware on a little PCB
that fits in a PGA.

2 kbyte cache.

Intel i80386DX CPU upward pin compatible.

16/32 MHz.
20/40 MHz.
25/50 MHz.


1.18.5 Cyrix Cx486DRx2 CPU

Clock doubled version of the Cyrix Cx486DLC CPU.

Incompatibilities: AT&T / Olivetti 386DX-16 and 386DX-20 systems,
Sun i386 systems,
Memorex 386 systems,
IBM PS/2 Model 70/16 MHz (85 ns memory required),
early Compaq Deskpro 386/16 MHz systems with 287 NPX (NPX
to be removed).

16/32 MHz: $279.
20/40 MHz: $329, heat sink.
25/50 MHz: $379, heat sink.


1.18.6 Cyrix Cx486SRx2

Intel i80486 CPU instruction compatible, no FPU.
Clock doubled.

The chip is placed over the surface mounted Intel i80386SX CPU. The original
CPU is disabled by using the FLOAT pin. Older 16 MHz Intel i80386SX CPU's can
not be upgraded.

1 kbyte cache.

20 MHz, 1993.
25 MHz, 1993.


1.19 Texas Instruments 386/486 hybrid CPU

1.19.1 Texas Instruments TI486DLC CPU

Cyrix Cx486DLC CPU.


1.19.2 Texas Instruments TI486SLC CPU

Cyrix Cx486SLC CPU.


1.19.3 Texas Instruments TI486SXLC2 CPU (Potomac)

Texas Instruments TI486SLC CPU instruction/pin compatible.
Clock doubled.

Power management.

8 kbyte internal cache.

33 MHz: 3 V, 1993.
33 MHz: 5 V, 1993.
20/40 MHz: 3 V, 1993.
25/50 MHz: 5 V, 1993.

100 pin QFP (Quad Flat Package).


1.19.4 Texas Instruments 386/486 hybrid CPU announcements

Rio Grande: Potomac follow-up.


1.20 Intel i80486 CPU

Intel i80386 CPU upward instruction compatible.
Extra instructions.

8 kbyte unified cache: write-through, 4-way set associative, 128 sets *
4 cache lines, 16 bytes per cache line, 4 write
buffers, only invalidation of a complete cache line.

32 bit internal data bus.
32 bit external data bus.
32 bit address bus.

RISC-like execution unit:
5-stage pipeline,
barrel shifter,
conditional jump taken / not taken prediction.

Burst mode memory access: first access: 2 clock cycles,
every next access: 1 clock cycle.


1.20.1 Intel i80486DX CPU

Build-in FPU.

20 MHz.
25 MHz, $219, 2600 mW, CHMOS IV.
33 MHz, $275, 3500 mW, CHMOS IV.
50 MHz, $499, 1991, 3875 mW, CHMOS V.

Upgrading: Intel i80486DX2 CPU (ODPR), Intel Overdrive CPU (ODP:
Intel i80486DX2), Intel Overdrive CPU (ODPR: Intel Pentium CPU with
Intel i80486DX CPU bus interface), Intel Overdrive CPU (ODP:
Intel Pentium CPU).

1989.

168 pin PGA (Pin Grid Array).

1.2E6 transistors.


1.20.2 Intel i80486SL CPU

Intel i80486DX CPU with extra features: DRAM controller,
ISA controller,
local PI-bus controller (Peripheral
Interconnect),
power management.

25 Mhz.
33 MHz.

Not Intel i80486DX CPU pin compatible.
196 pin PQFP (Plastic Quad Flat Package).


1.20.3 Intel i80486DXL CPU

Intel i80486DX CPU with extra features: SMM (System Management Mode),
stop clock,
power saving features.


1.20.4 Intel i80486SX CPU

No build-in FPU: Intel i80486DX CPU with FPU disabled,
currently FPU not implemented (resulting in a smaller chip,
plastic package).

One extra pin assigned to allow an Intel i80487SX NPX to dissable this CPU.
Not Intel i80486DX CPU upward pin compatible.
168 pin PGA (Pin Grid Array).

16 MHz, 1991.
20 MHz, 1991.
25 MHz, 1991, $85.
33 MHz, 1991, $129.
3.3 V.

Upgrading: Intel i80486DX CPU (ODPR: Intel i80486DX CPU with
Intel i80486SX CPU pin layout), Intel i80486DX2 CPU (ODPR:
Intel i80486DX2 CPU with Intel i80486SX CPU pin layout),
Intel Overdrive CPU (ODP: Intel i80486DX2 CPU), Intel Overdrive CPU
(ODPR: Intel Pentium CPU with Intel i80486SX CPU bus interface),
Intel Overdrive CPU (ODP: Intel Pentium CPU).

208 pin PQFP (Plastic Quad Flat Package).


1.20.5 Intel i80486SXL CPU

Intel i80486SX CPU with extra features: SMM (System Management Mode),
stop clock,
power saving features.


1.20.6 Intel i80486DX2 CPU

Clock doubled version of the Intel i80486DX CPU.
Intel i80486DX CPU pin compatible.

20/40 MHz.
25/50 MHz, 4000 mW, $299.
33/66 MHz, 4875 mW, $449.
40/80 MHz (announced).
50/100 MHz (announced).

Upgrading: Intel Overdrive CPU (ODPR: Intel Pentium CPU with
Intel i80486DX CPU bus interface), Intel Overdrive CPU (ODP:
Intel Pentium CPU).


1.20.7 Intel i80486DX3 CPU (announced)

Clock tripled version of the Intel i80486DX CPU.

25/75 MHz, 3.3 V.
33/99 MHz, 3.3 V.


1.20.8 Intel i80486 CPU announcements

3,3 V versions of existing and new Intel i80486 CPU's.


1.21 AMD Am486 CPU

Same core and microcode as Intel i80486 CPU's. Currently working on an own
implementation. In between there are CPU's with recompiled 486 microcode.
Intel i80486 CPU instruction/pin compatible.


1.21.1 AMD Am486DX CPU

Intel i80486DX CPU instruction/pin compatible.

33 MHz: 8-33 MHz, 1993, $306.
40 MHz: 8-40 MHz, 1993, $306.


1.21.2 AMD Am486DXLV CPU

Low power, low voltage (3.3 V) version of the AMD Am486DX CPU.

33 MHz: 0-33 MHz, 1993.


1.21.3 AMD Am486DX2 CPU

Clock doubled version of the AMD Am486DX CPU.

25/50 MHz: 1993 $417.
40/80 MHz (announced).


1.21.4 AMD Am486DX3 CPU (announced)

Clock tripled version of the AMD Am486DX CPU.

33/99 MHz.
40/120 MHz.


1.21.5 AMD Am486SX CPU

AMD microcode.

Intel i80486SX CPU instruction/pin compatible.

33 MHz, 1993.
40 MHz, 1993.


1.21.6 AMD Am486SX2 CPU

Clock doubled version of the AMD Am 486SX CPU.

25/50 MHz: 1993.


1.21.7 AMD Am486 CPU announcements

3,3 V versions of the AMD Am486DX CPU and the AMD Am486SX CPU.


1.22 IBM 80486 CPU

Intel i80486 CPU instruction compatible.


1.22.1 IBM 80486DX CPU

Intel i80486DX CPU instruction/pin compatible.


1.22.2 IBM 80486SX CPU

Intel i80486SX CPU instruction/pin compatible.

16 kbyte cache.


1.23 Cyrix Cx486 CPU

1.23.1 Cyrix FasCache Cx486D CPU

Intel i80486DX CPU instruction compatible, build-in FPU.

2 kbyte cache: write-back.

Intel i80486DX CPU upward pin compatible.

On-chip ventilator.

40 MHz: 1993.


1.23.2 Cyrix FasCache Cx486S CPU

Intel i80486SX CPU instruction compatible, no build-in FPU.

2 kbyte cache: write-back.

Intel i80486SX CPU upward pin compatible.

40 MHz: 1993.


1.24 Texas Instruments TI486 CPU

1.24.1 Texas Instruments TI486SXL2 CPU (Potomac)

Intel i80486 CPU instruction compatible, no build-in FPU.
Clock doubled.

Intel i80486SX CPU pin compatible.
168 pin CPGA (Ceramic Pin Grid Array).

Power management.

8 kbyte internal cache.

33 MHz: 3 V, 1993.
40 MHz: 5 V, 1993.
20/40 MHz: 3 V, 1993.
25/50 MHz: 5 V, 1993.


1.25 Intel Overdrive CPU for Intel i80486 CPU

Many 486 CPU motherboards contain an Intel Overdrive socket in which a more
powerful CPU can be placed (ODP: OverDrive Processor), this being an
Intel i80486DX2 CPU or an Intel Pentium CPU. It is possible to remove the old
CPU while upgrading. All output pins of the original CPU are put in 3-state
and the power consumption is reduced when the UP# pin (Upgrade Present) is
activated.

An Intel Overdrive CPU will be made available that will fit in the original
PGA (ODPR: OverDrive Processor Replacement), so motherboards without an
Intel Overdrive socket can be upgraded.

At this moment it is still unsure if all motherboards with an
Intel Overdrive socket can indeed be upgraded to an Intel pentium CPU. The
Intel P24T CPU, the Intel Pentium CPU upgrade for the blue 238 pin PGA
Overdrive socket, apears to produce too much heat for most thermally not
compliant systems. It is not even sure if there will ever be an
Intel Pentium CPU upgrade for those motherboards at all. For the newer
motherboards with a 237 pin PGA Overdrive socket, that do satisfy the heat
specifications, there will be an Intel Pentium CPU at 3,3 V with a ventilator
on the IC.

ZIF socket (Zero Insertion Force).


1.25.1 Intel i80486DX2 CPU for Intel i80486DX CPU (ODPR)

20/40 MHz: $285.
25/50 MHz: $359.
33/66 MHz: $459.


1.25.2 Intel i80486DX2 CPU for Intel i80486SX CPU (ODPR)

20/40 MHz: $285.
25/50 MHz: $359.
33/66 MHz: $459.


1.25.3 Intel i80486DX2 CPU for Intel i80486DX CPU or Intel i80486SX CPU
(ODP)

33/66 MHz.


1.26 Intel Pentium CPU

2-issue 5-stage superscalar with 8-stage pipelined FPU.
Intel i80486 CPU upward instruction compatible.

Multiprocessor support.
Upgrading: adding more Intel Pentium CPU's.

Parity checking at busses.

Branch prediction using BTB (Branch Target Buffer).

8 kbyte instruction cache.
8 kbyte data cache.
Both 2-way set associative.

64 bit data bus.
32 bit address bus.

60 MHz: 1993, 17 W, $1000 (First 66 MHz CPU's had heat troubles and were
released as 60 MHz items).
66 MHz: 1993.

P5.

Manufacturing: 0.8 micron biCMOS, 3.1E6 transistors.


1.26.1 Intel P54C CPU

Upgrading: Intel P54M Overdrive (2 CPU's co-operating).

1993.


1.26.2 Intel Pentium CPU announcements

3,3 V Intel Pentium-66/99 CPU
Intel Pentium-66/150 CPU.

P6: 8.0E6 transistors, Oregon.
P7: Santa Clara, CA.


1.27 Intel Overdrive CPU for Intel Pentium CPU

1.27.1 Intel P54M CPU

Overdrive for Intel P54C CPU.


1.28 VESA Local Bus (VLB)

The original VESA Local Bus was designed to work with CPU's using the 
Intel i80386DX CPU, Intel i80486DX CPU and Intel i80486SX CPU pinout (32 bit
data bus), running up to 40 MHz. There are also Pentium motherboards with
VESA Local Bus compatible slots.

A new version of the VESA Local Bus specification was released in 1993.




2 NPX

2.1 Intel i8087 NPX

NPX for Intel i8086 CPU, Intel i8088 CPU, Intel i80186 CPU, Intel i80188 CPU.

5 MHz (8087-3): $45.
8 MHz (8087-2): $49.
10 MHz (8087-1): 2400 mW, $85.

40 pin CERDIP (CERamic Dual In-line Package).

Technology: NMOS.


2.2 Intel i80287 NPX

NPX for Intel i80286 CPU, Intel i80386 CPU.

6 MHz.
8 MHz.
10 MHz: 2400 mW.

1983.

40 pin CERDIP (CERamic Dual In-line Package).

Technology: NMOS.


2.3 AMD Am80287 NPX

2.3.1 AMD Am80C287 NPX

Intel i80287 NPX instruction/pin compatible.
Intel i80287 NPX core/microcode.

10 MHz: $50.
12 MHz: $50.
16 MHz: $50.

1989.

40 pin CERDIP (CERamic Dual In-line Package).
40 pin plastic DIP (Dual In-line Package).
44 pin PLCC (Plastic Leaded Chip Carrier).

Technoloy: CMOS.


2.3.2 AMD Am80EC287 NPX

AMD Am80C287 NPX with power management.


2.4 Cyrix Cx287 NPX

Intel i80287 NPX instruction/pin compatible.

8 MHz.
10 MHz.
12 MHz: $69.
16 MHz.
20 MHz.


2.5 Intel i80187 NPX

NPX for Intel i80C186 CPU.

Intel i80387 NPX core/microcode.
Intel i80387 NPX instruction compatible.

12.5 MHz: 1989, 675 mW.
16 MHz: 1989, 780 mW.

40 pin CERDIP (CERamic Dual In-line Package).
44 pin PLCC (Plastic Leaded Chip Carrier).


2.6 Intel i80287XL NPX

NPX for Intel i80286 CPU, Intel i80386 CPU.

Intel i80387 NPX core/microcode.
Intel i80387 NPX instruction compatible.

Intel i80287 NPX pin compatible.

12.5 MHz: 1990, 675 mW, $85.

40 pin CERDIP (CERamic Dual In-line Package).
44 pin PLCC (Plastic Leaded Chip Carrier) (Intel i80287XLT NPX).

Technology: CMOS.


2.7 Cyrix Cx2S87 NPX

NPX for Intel i80286 CPU, Intel i80386 CPU.

Intel i80387 NPX instruction compatible.
Cyrix Cx83D87 NPX core/microcode (until november 1991)
Cyric Cx387+ NPX core/microcode (from november 1991).

6 MHz: 1991.
8 MHz: 1991.
10 MHz: 1991.
12 MHz: 1991, $69.
16 MHz: 1991.
20 MHz: 1991.

40 pin DIP (Dual In-line Package) (Intel i80287 NPX pin compatible).
44 pin PLCC (Plastic Leaded Chip Carrier) (Intel i80287XLT NPX
pin compatible).

Static core.
Technology: CMOS.


2.8 IIT IIT-2C87 NPX

NPX for Intel i80286 CPU, Intel i80386 CPU.

IIT IIT-3C87 NPX instruction compatible.
IIT IIT-3C87 NPX core/microcode.

Intel i80287 NPX pin compatible.

8 MHz: $29.
10 MHz: $39.
12 MHz: $60.
16 MHz.
20 MHz, 1989, 500 mW, $64.

Technology: CMOS.


2.9 Intel i80387 NPX

2.9.1 Intel i80387 NPX

16 MHz: 750 mW.
20 MHz: 950 mW.
25 MHz: 1250 mW.

1986.

68 pin, 2 row ceramic PGA (Pin Grid Array).

Technology: 1.5 micron CHMOS III.


2.9.2 Intel i80387DX NPX

NPX for Intel i80386DX CPU.
Enhanced Intel i80387 NPX.

16 MHz: $75.
20 MHz: 525 mW, $75.
25 MHz: 625 mW, $75.
33 MHz: 750 mW, $75.

1989.

68 pin, 2 row PGA (Pin Grid Array).

Technology: CHMOS IV.


2.9.3 Intel i80387SX NPX

NPX for Intel i80386SX CPU.

Intel i80387 NPX core/microcode.

16 MHz: 740 mW, $75.
20 MHz: 1000 mW, $75.
25 MHz: $75.
33 MHz.

68 pin PLCC (Plastic Leaded Chip Carrier).


2.9.4 Intel i80387SL NPX

NPX for Intel i80386SL CPU.

Intel i80387DX NPX core/microcode.
Extra features: cache controller,
programmable memory controller,
expanded memory support.
Static core.

Power management.

16 MHz.
20 MHz.
25 MHz: $75.
33 MHz.

1992.

Technology: CHMOS IV.


2.10 Chips & Technologies SuperMath 38700 NPX

2.10.1 Chips & Technologies SuperMath 38700DX NPX

Intel i80387DX NPX instruction/pin compatible.

Power Management.

16 MHz: 1991.
20 MHz: 1991.
25 MHz: 1991.
33 MHz: 1991.
40 MHz: 1991.

No longer available.

68 pin ceramic PGA (Pin Grid Array).

Technology: 1.2 micron CMOS.


2.10.2 Chips & Technologies SuperMath 38700SX NPX

Intel i80387SX NPX instruction/pin compatible.

Power management.

16 MHz: 1991.
20 MHz: 1991.
25 MHz: 1991.

No longer available.

68 pin PLCC (Plastic Leaded Chip Carrier).


2.11 Cyrix 80387 NPX

2.11.1 Cyrix FasMath Cx83D87 NPX

Intel i80387DX NPX instruction/pin compatible.

Power management.

Computations are executed faster than by Intel i80387DX NPX.

Later versions (from november 1991) correctly co-operate with first generation
Cyrix Cx486DLC CPU's, which were having synchronization problems, when
co-operating with a NPX.

16 MHz: $64.
20 MHz: $64.
25 MHz: $64.
33 MHz: $64, 500 mW.
40 MHz: november 1991, $59.

1989.


2.11.2 Cyrix FasMath Cx387+ NPX

European name for Cyrix FasMath 83D87 NPX from november 1991.

40 MHz: november 1991.


2.11.3 Cyrix FasMath EMC87 NPX

Also know as Cyrix AutoMath.

Cyrix Cx83D87 NPX with extra features: memory-mapped mode.

25 MHz.
33 MHz: 2000 mW.

121 pin PGA (121 pin EMC: Extended Math Coprocessor)


2.11.4 Cyrix FasMath 83S87 NPX

Intel i80387SX NPX instruction/pin compatible.
Cyrix Cx387+ NPX core/microcode after november 1991

Power management.

Computations are executed faster than by Intel i80387SX NPX.

16 MHz: $57.
20 MHz: 350 mW, $57.
25 MHz: $57.
33 MHz: $75.

68 pin PLCC (Plastic Leaded Chip Carrier).


2.11.5 Cyrix Cx387DX NPX

Intel i80387DX NPX instruction/pin compatible.

16 MHz.
20 MHz.
25 MHz.
33 MHz.
40 MHz.


2.11.6 Cyrix Cx387SX NPX

Intel i80387SX NPX instruction/pin compatible.

16 MHz.
20 MHz.
25 MHz.
33 MHz.


2.12 IIT IIT-3C87 NPX

Not fully Intel i80387 NPX instruction compatible.
Extra features.


2.12.1 IIT IIT-3C87 NPX

16 MHz: $69.
20 MHz: $69.
25 MHz: $69.
33 MHz: $69.
40 MHz: 600 mW, $69.

1989.

Intel i80387DX NPX pin compatible.

Technology: CMOS.

1.12.2 IIT IIT-3C87SX

16 MHz: $69.
20 MHz: $69.
25 MHz: $69.
33 MHz: $69.
40 MHz.

68 pin PLCC (Plastic Leaded Chip Carrier).

Technology: CMOS.


2.13 ULSI Math*Co 83C87 NPX

Intel i80387DX NPX instruction/pin compatible.

20 MHz: 400 mW.
25 MHz: 500 mW.
33 MHz: 625 mW, $59.
40 MHz: 750 mW, $59.

1991.

68 pin ceramic PGA (Pin Grid Array).

Technology: CMOS.


2.14 ULSI Math*Co 83S87 NPX

Intel i80387SX NPX instruction/pin compatible.

Power management.

16 MHz: 300 mW.
20 MHz: 350 mW.
25 MHz: 400 mW.

68 pin PLCC (Plastic Leaded Chip Carrier).


2.15 Weitek Abacus 1167 NPX

NPX for Intel i80386Dx CPU.

Not Intel i80387 NPX instruction compatible.

In fact a small PCB with three chips mounted on it.
Not Intel i80387DX NPX pin compatible.


2.16 Weitek Abacus 3167 NPX

NPX for Intel i80386DX CPU, Intel i80486 CPU.

Not Intel i80387 NPX instruction compatible.

Not Intel i80387DX NPX pin compatible.
121 pin, 3 row PGA (Pin Grid Array) (EMC socket).
Can be used together with Intel i80387DX NPX. If the motherboard has no apart
PGA for the Abacus, two NPX's can be used simultaniously by installing an
extra PCB, containing two PGA's, on the original PGA.

20 MHz: $29.
25 MHz: 1750 mW, $79.
33 MHz: 2250 mW, $169.


2.17 Cyrix Cx4C87DLC NPX

NPX for Cyrix Cx486DLC CPU.

25 MHz.
33 MHz.
40 MHz.


2.18 Intel i80487 NPX

NPX for Intel i80486SX CPU.


2.18.1 Intel i80487SX NPX

In fact an Intel i80486DX with different pin layout (in Intel i80487SX NPX
socket) and one extra pin assigned to disable the Intel i80486SX CPU. The
Intel i80486SX CPU can be removed.

20 MHz: 3250 mW.
25 MHz: $329.

169 pin PGA (Pin Grid Array).


2.18.2 Intel i80487 NPX

In fact an Intel i80486DX with Intel i80486SX pin layout (in
Intel i80486SX CPU socket).

25 MHz: $329.


2.19 Weitek Abacus 4167 NPX

NPX for Intel i80486 CPU.

Not Intel i80387 NPX instruction compatible.

25 MHz: 2500 mW, $299.
33 MHz: $529.

142 pin, 3 row PGA.