What is your undervoltas (ie Vcore = XXXX at idle and under load).
@ 4.0->4.2 probably a good vcore would be around 1.25 -> 1.3 und load.
Intel max is 1.5V, but would recommend staying below 1.4
NOTE: Max voltage for Ram is 1.575 per intel spec. (Note some have used 1.65 V Ram, I have 1.60 v Ram)
I see the voltage vary from about 0.77 to 1.38, so the voltages are in a good range, it just seems that under load when overclocking, the MB can't keep up (this is just my thinking) with the changing demands, and I get sporadic undervoltage situations. I'm thinking that if I just set the voltage to something like 1.35 and leave it there, I won't run into this situation in the future.