I've noticed clrmame exhibits very slow performance when performing any task while the folding@home client is also running in the background. It appears the thread clrmame uses for scanning, loading profiles, etc is somehow being forced to compete with the folding client for CPU time (is it being set to idle priority somewhere?) Stopping FAH instantly brings clrmame back to full speed.

Needless to say this is kinda annoying and really should not be happening. It may be related to x64 windows since I didn't notice it until I upgraded to XP x64 (it also happens under Vista x64).