Just wanted to confirm splaves experience. I just had some weired behavior. Was testing some 4790K and 32m passed 5 GHz at 1,40 volt. Lowered to 1,375 and didn't even boot XP. Set back to 1,40 Volt and still didn't boot. Had a big WTF moment. Even switched to another mainboard.
Then remembered this topic and lowered VCCIN to 1,60 Volt. And 1,40 vCore was working again.
Lowered to 1,55 Volt even 1,375 Volt is running 32m now. I can't explain this but it works