I do 1.4v which ends up as 1.38. I can hit 4.35 with that. In windows I reached 4.40 at that voltage but I mainly run linux on this one and it kept getting weird over a certain bclk. With ht off I could get as high as 4.55.
I thought I remembered reading an article on toms that it frys at 1.47 or something like that. Maybe I am wrong but intel max is 1.4.