Hey there I have the same CPU as you, and mine is good for about 2.6 GHz. But I will tell you right now, it was NOT with that Epox board. The Epox was my first board choice (nice and cheap) and it was awful, voltages were totally unstable, and therefore OC was ok one minute and crashing the next. So I traded it in on a DFI Lanparty (which is now only $94 at Newegg right now) and what a difference it made. The DFI does a better overclock at lower vcore.
I really think the board is the cause for your bad overclock and not the CPU.