did you just use the muti or use fsb in addition to multi to overclock? what are your nb and ram volts?
I am using only the multiplier for oc'ing. I have a 200MHz core * 18 multiplier to make 3.6GHz.
My north bridge is set to go between 1.1 - 1.25V, which is Auto.
My ram is set to be at 7-8-7-24 @ 1.6V, which is the default.