A small note:
Remember that when you're overclocking a processor you not only have to pay attention to cooling and voltage, you also have to pay attention to the North Bridge (memory controller hub) and the actual RAM itself since they are overclocked as well. I have a Q9550 E0 Stepping that's been overclocked to 3.6 GHz for over a year and not a single BD RB error to report. The processor can be pushed to 3.8 GHz and appear to be running stable. Once I've found that point high point I then begin to back it down to reduce voltage settings and heat to insure maximum stability.
Since I started using DVD Rebuilder back in 2004 I've come across overclocking issues so many times in forums that it is one of the first areas that I question. I'm all for overclocking but if you're going to do it make certain that you've checked every part on your computer that's affected by it, and insure that they're all in working order before involving others on what could be a wild goose chase.