At 08:38 PM 1/19/1999 Wayne Rowlinson wrote:
>
>        I'm having a problem with a system I'm working on for a friend.
She has
>an Intel DX2-66 CPU that I'm trying to put into her motherboard, but the
>board will not work at any bus speed other than 40.
>        It is supposed to support 25,33,40, and 50MHz bus speeds, but
simply will
>not work at the other bus speeds.  I know for a fact that all the jumpers
>are correct. . . .
>        Does anyone have any stories on overclocking this chip. . . . ?


Wayne:

What kind of motherboard are you using? Most 486 motherboards
have different settings for the various CPU brands, in addition
to the clock and multiplier settings, since 486 CPUs are not
strictly interchangeable because the chipsets weren't tolerant
of the variety. See if there is a separate setting for Intel CPUs.

If you have a 3.3 volt CPU and adequate cooling, it should overclock
at 40MHz okay. The Intel 486DX CPUs are normally 5 volts unless the
CPU specifically states (on the chip) that it is 3.3 volts. Most of
the 3.3v Intel 486s were DX4-100s but I recall seeing a couple DX2s
that were 3.3 volts.

After a point, it is not worthwhile spending money on a 486 system.
Classic Pentium motherboards and CPUs cost the same as 486 parts,
about $80 for a FX or VX class motherboard and a 166MHz Pentium
processor. Double that money and you can get a Celeron 300A and a
AT form factor motherboard. Assuming you have pairs of 70-pins SIMMs
and a PCI video card, that sort of upgrade makes more sense.

Best of luck.

John Chin

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