At least PowerMizer does work with the binary driver for automatically switching between performance levels. While PowerMizer works, after running the tests I realized there was a slight problem... The third (highest) performance level indicates a 705MHz core clock, 3004MHz memory clock, and 1411MHz processor clock. Okay, the GDDR5 memory clock is right, but the rest are not; the graphics core clock is some 300MHz too low. The performance level two is also the same as the performance level three. In checking what the Phoronix Test Suite was reporting, which reads its values using the nvidia-settings extension and in the case of clock frequencies via the "GPU3DClockFreqs", it too found the GK104 core topping out at 705MHz rather than 1006MHz.
In contacting the NVIDIA Linux team, they investigated and at first thought it might have been a defective video BIOS or other issue. However, in the end the NVIDIA Linux developers believe the card is operating correctly, it's just not being reported as such. With Kepler each of the GPU's performance levels has a range of frequencies and so they think it's basically just showing the low-end values. However, the reporting should be improved in a future release. For more details see this news posting: http://www.phoronix.com/scan.php?page=news_item&px=MTA4ODc
__global__ void wait( long long int *a, int n )
long long int c0 = clock64(), c1;
while( (c1 = clock64() - c0) < n );
*a = c1;
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