What is the difference between CUDA clockrate and GPU clockrate?

Accelerated Computing CUDA CUDA Programming and Performance
1

Hi folks,

the clockRate variable of the cudaDeviceProp structure shows, that my GTX285 has a 1476 MHz clockrate. The nvidia-settings tool displays 648 MHz (on highest performance level) instead.

What’s the right rate? Is the card possibly underclocked?

CUDA 2.3
GTX 285
openSUSE 11.2

2

Nvidia GPUs have three clocks. The “hot” clock, which is the speed that individual stream processors and fixed function pipe line stuff run at, the shader clock, which is the speed that the scheduler and associated hardware runs at, and the Memory clock, which is the speed that the memory controller runs at. For a standard GT200 consumer card the “hot” clock should be something around 1.4GHz, the shader clock 650MHz and the memory clock 1GHz (frequency doubled at the DDR memory).

So your GTX 285 sounds absolutely normal to me…

3

thanks :-)