On 24 Mar 98 at 17:39, John Chin wrote:

> I have seen motherboards with dual voltage settings that are
> NOT P-55C compliant (MMX).
>
> "The MMX CPUs won't work," said a Shuttle Co. technician said
> of the older Spacewalker motherboards albeit with split voltage.

  That's bizarre.  The only non-MMX split-voltage CPUs I know of are
the IBM 6x86-L/Cyrix 6x86-GP (same chip, different label), and those
can't be all that common.

> If you do get the CPU to actually work, the MMX instruction set
> will likely NOT work.  This is regardless of any BIOS upgrade.

  Weirder and weirder.  The only interaction I know of between BIOS
and MMX is whether the CPU type is correctly identified on the boot
screen.

> With the K-6 200 (MMX) just under $100 and decent P54C/55C
> motherboards starting at $70, it makes little sense to try this
> upgrade when the chances of success are nil. Sell your existing
> CPU/motherboard for $70 or more and upgrade the subsystem,
> and you will be ahead of the game.

  True.  In fact, if I were in the market for an MMX CPU, I'd be
looking for something at least a step above a 430FX to run it on.

David G