search on apples site for “CHUD tools”, they may also be on your installation disk and be installed if you install xcode and all developper files.
Anyway, CHUD ads a control-panel to the system preferences where you can set a few processor-options like “allow nap” or “use only 1 processor”.
I’ve disabled “allow nap” because if it’s on, I can hear the graphics card whirr with a very high pitch whenever I drag a window in the finder.
(yeah I know, it’s weird)
But it might solve your problem too.