Similar problem here too. MULE pushes my cpu to 100% as soon as graphics start displaying, I manage to get to end of a round sometimes before my machine becomes really unusable.

Linux blue 2.6.31-16-generic #53-Ubuntu SMP Tue Dec 8 04:02:15 UTC 2009 x86_64 GNU/Linux

01:00.0 VGA compatible controller: nVidia Corporation G72M [GeForce Go 7400] (rev a1)