>> For NetBSD, or SPARC systems in general.  mbus.sunhelp.org claims you
>> can mix different speeds, provided the cache controllers have the same
>> major rev, and you don't cook too much with the extra heater, etc.
>
>SPARC systems in general.

We had a Sparc20 at work that had (I believe) a SM71 and a Ross
Hypersparc 125Mhz in it, and it worked fine under Solaris.