some think its the speedswitching, I really dont know for sure.
for those who dont know, the problem is this: when you open mach, the whole system comes to a near hault. Whether it will output pulses or not Im not sure.
What some have suggested is disable speedwitching. another thing you want to do is close every ap, I found recently that running msn messenger 7 caused my computer to do the same thing with mach running.
Jon