Not sure what the deal is but for some reason certain voltages will cause Windows to bluescreen before it finishes loading and I have never experienced anything like this before so not sure where to even start.

Essentially I have a stable OC 3.8ghz w/turbo on and HT off (i7 920). I wanted to turn HT on so I did and it boots into windows fine at my previous voltage 1.3625 in bios (Anything less was not stable with HT off) now I am no longer stable because of HT so I figure I need to up the voltage some on the processor. I go into the bios and raise voltage from 1.3625 to 1.3875 and now windows starts blue screening, wont finish loading. So I go back into bios lower voltage to 1.375 now it boots, I can crank up the voltage to 1.4 and it will also boot but it refuses to boot at 1.3875.

Anyone ever seen anything like this before?

Trying to get 4ghz but it's damn near impossible when random voltages will cause such severe instablity. I suspect I have something bad, memory, cpu or mobo but not sure how to know what's what being that the memory controller is now on the cpu it makes it rather hard to figure out via process of elimination.