I attempted 4.5GHz@1.37v last night and it crashed about 6.5 hours in. >_<
Some may say (one person already did) that that is stable "enough" but he then remembered that I do in fact render - thus I need absolute stability. =/
So I'll be sticking at 4.5GHz@1.375v, may try 4.6GHz@1.41v later tonight, if that doesn't work, 1.42v, but I think that may be my personal cap... it is just such a jump in voltages for only 100MHz more.
Hell I'm debating knocking my CPU back to 4.4GHz just because then it doesn't need the internal PLL overvoltage enabled and such. =/