what bios are you running simkin? air or water cooled? i'd say SPU PLL, FSBT, NB, voltages are important. hell, all are important. what i did is looked in the manual for the highest normal settings (except for DRAM) and set it to that. i worked my way back from there to find what was stable. that was for the 3.8 though. 3.9 was another story.
using 0602 bios

run it on air, Noctua NH-U12F

if i set it to 3.6, what should the voltages be on? i have tried some of the voltages other people are using on 3.6 in here, but 79 celsius is a bit hot. and i get error in stress test

on 3.4 its 68 celsius full load