On Tuesday 15 October 2002 04:18 am, rowland wrote: > On Monday 14 Oct 2002 11:23 am, J. Greenlees wrote: > > Thierry Vignaud wrote: > > > also, the 486sx (at least the first ones) did has a coprocessor; it > > > was disabled but was still there (though i don't rember if it was > > > missing pins or some silicon hack).
> > actually, it was a bad bit of circuit if I remember correctly, the co > > pro was completely un-usable because of it and the cpu was a lower price > > for that reason. > if I remember rightly it was a batch of i486dx's that had this problem, > the fpu just couldnt add up properly given the right set of circumstances > and intel had to change all the affected chips! 486sx was 486dx sans FPU and on a skinnier buss. To add an FPU, you bought a 487sx chip, which was really a 486dx that had failed some factory tests and been packaged for the skinnier buss. For a little while, some motherboards had an option to run with _only_ a 487sx, because they were significantly cheaper than a 486sx and usually worked fine (sometimes faster, because a 486sx had no CPU cache at first but many of the 487sxes did). Cheers; Leon
