windows aero performance 3D?

I have noticed in Windows 7 beta my card runs at full gpu clock under windows aero... I have a GTX 285. The card is not overclocked and runs at 675 mhz, temps in the upper 40's. If I switch to a simple theme, without windows aero, it throttles back to the 2D settings of 300mhz. Is windows aero designed to cause the driver to detect performance 3D? It seems it would at least be low power 3D and run at the 400mhz. I have tested and confirmed with both EVGA Precision software and rivatuna.