I have tried overclocking my FX-6100 to 4,2 ghz on 1.35v. Everything is okay until i run prime95 for a couple of minutes, because then my clock speeds drop really low (1,4 ghz) according to core temp and also my voltage drops to 1.0.
I have disabled CnQ, core 6 state and windows is on high power mode. I know that it can't be temperature problem because at stock speeds i can run prime95 for hours and hours and never exceed 50c.
12 gb HyperX 1600 mhz ram
Asus gtx 560
Asus M5A7L-LE mobo
XFX Pro 550W psu
I know its off topic but why are you running prime95 on stock for hours? If that 50c is the core temp on stock thats hot enough and it sounds like the cpu is throttling to protect its self, if your using the stock cooler i suggest not to overclock or to invest in a aftermarket cooler