Prioritizing OpenCl kernels OpenCL to process realtime audio effects

I’m using OpenCL to process realtime audio effects (mainly based on convolution).
In current implementation, my audio driver requires the process time of each audio bloc to be under 11,6ms (512samples @44,1kHz).

My current implementation works well, and process time is around 7ms. So everything is fine until, someone else needs the card.
When I resize a window under Win XP, the GPU is used, and my processing time goes up to 14ms. And so my audio cracks.

I a using 2 NVidia 8800GTX cards, and the questions are the following :

  • Is it possible to affect priorities to my kernels, so that I keep real time processing, an avoid cracks (I mean higher priority, than win XP graphical display).
  • My OCL program runs on a single card, is it possible to execute all Windows XP operations on the other card (so that the first one is used only for real time audio processing).