On Mon, 17 Nov 2003, Dave McGuire wrote:

>    Well I don't remember where I got 25MHz, it's been in my head for at
> least a decade.  But I can tell you for certain that the 78032 on a
> KA630 is clocked at 20MHz, as I've overclocked a couple of them...so
> that would seem to support the idea, as I doubt its successor would
> have a lower clock rate.

Maybe the KA630s had a crystal oscillating at 20MHz, but the CPU cycle
time is listed as being 200ns (5MHz) in the VARM.  DEC most probably
divided up that 20MHz crystal output, using only a fraction of it for
CPU timing.  It'd certainly be interesting to know what was going on at
a very detailed hardware level, but I'm not much of a computer engineer.

-brian.