>The 486 was the first to offer an on-chip FPU, came out at 20 and
>25 Mhz and went to 100 Mhz (core=3x memory bus)
>in the Intel line, 133 (4x) elsewhere (AMD?). The 486 socket's performance
>could be stretched a little further by using a Pentium Overdrive chip
>from Intel; at 83 Mhz (2.5x) giving 1.7x the performance of a 486-66
>in real world finite element analysis (ANSYS). The 486SX was a
>no-fpu 486, with full memory bus width.
>
>The Pentium I's in various subflavors went from 60 & 66 at announcement,
>to 200 (nonMMX) and 233 in the MMX type.
>
The i486 came out in two flavors, the SX and the DX. The 486SX ran at 25
mhz, and had no FPU. The DX ran at 33Mhz, and had a FPU. The SX mobos
had room for a math coprocessor, which was BS. The math co was just a
486DX chip which disabled the SX chip. The line was continued with the
SX50, DX2 66Mhz and later with the DX4 100Mhz part. Buying the DX4-100 was
pretty much a moot point because of the slow memory bus speed. It gave me
little or no performance gains in GIMPS competiton, and cost several hundred
bucks. All of this I am 100% sure of.
The Pentium chip came out at 60Mhz, and went to 75 and 90 within months of
release. It went up to 200Mhz.
I just looked and found a little processor history page:
http://www.ambusiness.com/NT512200.html
In my collection I have a ~700Khz TI/99/4A and a 2.6Mhz Apple IIgs.
-Brian
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