It was stable for about an hour of prime 95 at 1.195v but then blue screened on me. Is 1.2v safe or should I go down to 4.1Ghz where I was at 1.850v? My heat sink is a Xigmatek Dark Knight and it hits 70c under load with prime 95.
1.2v is fine if your temperature is only 70c under load (Prime95). My 4670K is clocked at 4.6Ghz @ 1.265v and I have had zero issues. You're completely okay at that clock and voltage! Hope this helps!