[Tfug] Intel CPU compatibility

[Bexley Hall]

Hi,

I want to upgrade the processors in my SGI VWS.
IIRC, it is currently configured as 1x450 (or maybe
2x450?).

But, I don't know what all of the criteria are for
"CPU swap"  :<

Obviously, CPUs need to be in compatible packages
(these are  :> ).

And, FSB must be same speed.

And, for pairs of CPUs, they need to be same stepping.

But, are there other more subtle issues?  E.g.,
does the VRM "auto-sense" the CPU and adjust Vout
accordingly?  Or, do you have to fit the correct
flavor VRM to the processor?

The replacement processors (P3's) are labeled
"800/256/100/165V".  I assume these to probably
indicate CPU speed, onboard cache, FSB speed and
VRM voltage"?

If so, the first two values should be able to vary
wrt my old CPUs (i.e., old CPU will undoubtedly be
slower, possibly have a different amount of cache).
The third value must agree (i.e., a 100 FSB wouldn't
work *reliably* in a 133 FSB system -- and, I don't
think you can *authoritatively* claim that a 133FSB
CPU would work in a 100FSB system since so many
of these things now have PLL's onboard and you
can't be sure how wide the capture range is...)

So, is the last value "for informational purposes"
or must it agree with the corresponding value in the
existing system?  (I'll have to pull the case off and
see what the current markings are)

Thanks for any help clarifying the alphabet soup!
--don