geforce 285 vs 460 on widows 7

Hello everyone,

I had a quick question comparing gtx 285 and gtx 460/480 performance on windows 7 and windows xp OS. I do know that due to the WDDM in windows 7 the performance of CUDA is slightly hindered in comparison to windows xp. But i see a drastic difference of this effect between gtx 285 and gtx 460 GPU’s. Here below are some timing numbers for kernel execution and standard CUDA calls.

Windows Xp w/gtx 285 ~= 660 ms

Windows 7 64bit w/gtx 285 ~= 1340 ms

Windows xp w/gtx 460 ~= 500 ms

Windows 7 64bit w/gtx 460 ~= 530 ms

Similarly certain basic cuda calls like cuda malloc, cuda_synchronize are nearly twice as slow on an windows 7 machine with gtx 285 when compared to that in xp with gtx 285. But they are nearly the same when the system have gtx 460/480 GPU’s.

So my basic question is, does windows 7 have this huge effect on 200 series cards and have a negligible effect on 400 series cards.