Instead of theorizing so damn much, you should try to get the clocks under Windows with ATITool or winclk.
ok gimmie a min
edit:
lol ok, so im regretting taking that guys advice. i downloaded the program and then the imac screen went black. it now runs but with no screen...lol im typing this on my pc. grrreeeeat!!
lol anyone know anything i can do (other than never download crappy graphics programs again) ?!! eek!