I have an Athlon TBird 900 (ovrclk'd), 768MB and QuadroDCC (W2k).
I have a 17MB .mb scene open and minimized, and the teskmanager is telling me that maya.exe is getting no clock cycles at all. zero.
you must have something actively "solving" or somesuch inside of Maya.
hmmm. intersting.
kiwi