I'm at BIOS 1402 (1403?) right now and I can get 3.24Ghz OC with all Voltage settings on Auto.
I put bios 1602 in and I think it sucks. I couldn't even get 3.0 Ghz stable with a lowered NB speed and a voltage bump CPU&NB.

It also kept saying unleashed mode failed. With ACC on and with it off.