Did you change voltage at all? Senior overclockers please correct me if i am wrong but this is my approach.
Bamp voltage to 1.4 and change multiplier to 4.5ghz
Make sure to download HWMonitor to monitor your temps and voltages.
alternate running prime 95 for a good while and raising multiplier to see how far you can get on 1.4 volts
when prime tells you "a worker has crashed/ stopped" you can increace voltage some more and try priming it again or you can back down the freq untill prime is happy. at i think the 15-20 minute mark is when prime really starts punishing your cpu and you will experiance max heat. (just food for thought)
Be weary of your temps because AFAIK its not the voltage that kills you but the high tempertures.
(written at 1:05am so please excuse the mistakes in my writing XD)
I have my 8320 purring at 4.4ghz @1.392 volts
http://www.mersenne.org/freesoft/ (prime95)
http://www.cpuid.com/softwares/hwmonitor/versions-history.html (HWMonitor)
http://www.cpuid.com/softwares/cpu-z.html (cpu-z)