why the frequency of Tesla C1060 steps down on windows

there is a strange problem with my two Tesla c1060 cards. When they run on windows xp, the geometric frequency, the shader frequency and the foreign frequency all step down to about 60% of original frequency. Detailed data as follows:

now geometric frequency: 400MHz
original geometric frequency: 610MHz

now shader frequency: 799MHz
original shader frequency: 1296MHz

now video memory foreign frequency: 297MHz
original video memory foreign frequency: 800MHz

So the “bandwidth test” in quick mode illustrates that the device to device bandthwidth is just 73311MB/s, there is a big gap between the original bandthwidth of c1060(about 102GB/s) and 73311MB/s.

I have tried the latest driver(190.00 for tesla c1060 and 191.07 for GT200)

Thanks for your help!

yeah, it slows down when the card is not in use. when it is, it hits full clocks (always). BW test usually reports 73GB/s, I think because of its particular mix of operations and overheads.

Pretty much every card I’ve tested gets 70-80% of the theoretical memory bandwidth using bandwidthTest.