Best Prime95 config to test CPU in shortest time?

What is the best prime95 configuration of the torture test to test if the CPU is stable in the shortest amount of time? I'm looking for:

Min FFT size (in K)
Max FFT size (in K)
Run FFTs in-place?
If no, what memory to use (assume I have 1GB)
Time to run each FFT (in minutes)


thanks