I was running a stress analysis this morning and I noticed in Resource Monitor (Win 7 64 bit) that two or three of my cores were greyed out and the status was listed as "CPU Parked" with 0% activity. My understanding is that stress analysis can take advantage of multiple cores, so I was confused as to why this might be.
After searching Google, I discovered that Win 7 actually does this as a power management feature (Go, Go, Green!) referred to as "Core Parking". A couple of the threads that I picked up on were by gamers, who said they had increased fps on games and less jittery graphics after disabling this feature. There is a regedit procedure to force Win7 to use all cores, all the time.
Just thought someone with graphics issues might try this as an additional troubleshooting method, or someone looking to tweak that extra 5-10% out of their system performance.