At 12:21 AM 7/17/1998 Joel Bluming wrote:
>
>I have a 486 motherboard as follows: OPTI-895GREEN 486WB. I have the
>manual. Currently I am running it with an Intel 486 DX4-100MZ CPU. I
>would like to replace the CPU with an AMD AM486 DX4-120 (but at 100MZ).
>Thew markings on the chip are - A80486DX4-120NV8T. The chip says 3 volts;
>does this mean 3.3 volts?
>
>From what I can guess in the manual, all the jumper settings are the
>same for both CPUs.


Joel:

Most 486 CPUs rated for 3 volts run okay at 3.3 volts.
A few will give random errors after a while. Very few
486 boards can be set for 3.0 volts. Put a good cooling
fan on the CPU.

I don't see any gain in running an AMD AM486 DX4-120
at 100MHz (i.e., 33MHz bus at 3x clock). The advantage
is running the memory bus at 40MHz at 3x for this
120MHz CPU so you get a 20% boost in RAM access
time and 20% in calculating power.

There usually are different settings for various 486
CPU makes and models. I expect you will have to use
different jumper settings if you switch from INTEL to a
AMD CPU.

Regards,

John Chin