CPU usage problem "Processor Device Driver" (intelppm.sys) usage problem


I have the problem. My Application has two threads - one of them runs on CUDA, while another runs at the CPU.
When I launch my application under CUDA I see the “Processor Device Driver” (intelppm.sys) process which is also running and uses 40% CPU, but my application uses only 20% CPU.
How can I fix this problem?

My operating system is Windows XP SP3, CPU Core2Duo E7400@2.80GHz, GeForce 9600GT ( driver version 185.85)