You really want to have total control over most of the parameters in the BIOS with regard to over clocking, especially the voltages. Sticking them on AUTO means the motherboard will set them according to the OC settings you've set but i've known the motherboard to over do it, even at low OC's that don't warrant vcore increases.
So take control of the voltages and only start to up them, a little at a time, to stabilize an OC.
To start off you really need to find the maximum BCLK for your set up and that means lowering the RAM/UNCORE/QPI multi's so they don't get in the way, but not too low so they themselves cause instabilities, when your finding the max BCLK.