In order to try to fix my quad-core stuttering I went to Windows 7 Ultimate. After a fresh install the stuttering was still present. After looking closely at my case I found that my rear 250mm fan was dying/dead and barely moving. Also found the mobo temp was way too hot and the CPU temp was just under thermal shutdown. This might be why my computer was shutting down at times with no warning.
In order to save my system I ditched air cooling and went with a Corsair H50 water cooling setup. My idle temps are now 35C to 39C down from 50C to 55C on air. My load temps are now 40C to 45C down from near 60C to 65C. Of course these temps are not internal core temps. One program reported my cores on air at around 55C to 56C. Thermal shutdown for AMD Phenom II's is supposed to be 62C although that sounds awful low.
After playing several games that used to glitch I have found that with the new cooling system none of my games glitch or stutter. NBA 2K11 is smooth as silk as well as a host of other games that used to have problems. The underside of the mobo near the CPU has an obvious different holdout or appearance on the substrate surface than the rest of the board. This is very visible from certain angles which indicates to me that the board has gotten a tad bit warm in these areas.
No more air cooling for me ever again. It is simply not enough to cool down a high performance system.