Even minimal overclock (5%) will result in unstable system.

[illuminator3]

I am running an amd phenom ii x4 940 (non black edition). I've installed a tuniq 120 cpu cooler. Even after installing an aftermarket cooler, I can't seem to overclock successfully. My system is perfectly stable when I leave the cpu at stock settings, even under load. I have verified this with prime 95. But when I overclock my cpu just 5% from 3.0 ghz to 3.15 ghz, and I run prime 95 or play a game, the system will crash within 5 minutes. I know temperature isn't the issue because at stock speed, my system idles at 38 C. I've tried various combinations of multipliers and voltages, but nothing seems to work. Could I possibly just have a defective cpu, or what is going on here? I have disabled amd cool n quit.

 

[pauls3743]

I assume you're adjusting the front side bus frequency. This doesn't just increase the cpu frequency it also affect other components. Some memory can't handle overclocking. Try decreasing the memory multiplier, effectively underclocking the memory.