Kralizec Craig <cd@lios.apana.org.au> probably said:
>You should never, ever combine CPU modules of different
>speed/type. If you can, obtain another 50 or 60 MHz module and use
>them in matched pairs of the same speed/type.

While this is what sun will tell you ("Mixing different CPU modules is
not supported") in practice you can mix CPU speeds in SS10s and SS20s.

MBUS modules will coexist at different speeds as long as the MBUS
speed is the same between the two modules, if the modules don't have
cache this means they run at the same CPU speed, if they do have cache
(SMx1 modules) then the bus speed is independant of the processor
speed and they can be mixed if the bus speed is the same.

I've seen SM51s and SM61s mixed quite happily (and still are, that
machine is still running) for a long time in an SS10 and tested
briefly other combinations in SS20s.

The only real negative aspect of doing this is that Solaris assumes
all processors are equal for purposes of scheduling, so CPU scheduling
priorities may be slightly sub-optimal.

P.

--
pir