Andrew P. Black wrote:
  With both OSs, I
> have Virtual Memory turned on, but set at 193MB on a machine with
> 192MB of real memory.  In both cases, there is more than 90MMB of
> unallocated memory, so there should not be any paging.

Try turning virtual memory off anyway. All timing critical tasks, like playing 
quicktime films etc. recomend turning it off. Probably the same is true for
Squeak, every time Squeak loose priority to mac os it will halt for a few 
milliseconds. 
Karl