Soldato
Well I got it in and running already lol
Been running haven benchmark and no issues with my 6700k @ 4200mhz
I undervolted it to 1050mv as well and so far seems stable.
Vega 64 is weird card, requiring more than brute force.
You can go all way to 970mv before it start crashing at default 1630 P7 clock. Of course it wont work at that clock, but it will try to do as high as possible given the voltage cap.
I have some overclocks posted on page 284 with 1030mv and 1652 clock (P7), resulting to stable 1620s at 240W on the nitro+. While another user got 26011 graphical score on Firestrike with the same settings. (thats higher than GTX1080 @ 2164)