In message <mtu1ytsmbw9.fsf@contents-vnder-pressvre.mit.edu>, Nathan J. William
s writes:

>
>This doesn't really depend on the CPU clock speed, but if VirtualPC
>isn't delivering the interrupts we asked for, there's going to be
>trouble. We don't currently have a way of noticing "hey, the
>hardware's dropping lots of clock interrupts!" and somehow
>recalibrating to that level of lossage.

I wonder if NTP could cope with that much irregularity in the clock 
interrupt frequency.  Do you have NTP on the Mac?  Does VirtualPC have 
pseudo-Ethernet connectivity to the Mac?

		--Steve Bellovin, http://www.research.att.com/~smb