speaker buzz..

I got a problem with my computer it seems that when ever the cpu is idle and I move the mouse I get a buzz out of the speakers, And I just foudn the same thing on my parents computer. mine is an 1800 amd with xp pro and theres is an 1ghz celeron with xp home. doesn't bother me much anymore since I have FaH running on them, but just wondering if anyone has any idea why it does it at first thought it was interference, form an electrical source, but after lots of trouble shooting bypassed that idea and found out its only when the cpu is idle. Any ideas would be appreciated

it has to do with the changes in current when you move mouse, and the psu. some psus do it, others do not. do a little searching and you can find an excellent explanation of the problem.

o yeh run folding@home, to eliminate the problem. 100% cpu usage all the time.