I can't be certain, and probably only AMI truely know the full meaning of their POST codes but F1 is probably triggered by a failed OC attempt... or maybe when the UEFI detects applied overclock settings. I'd have to ask my contacts if they know more to give a fuller answer. I've never seen POST code F1 on my Extreme4 unless its been a failed OC attempt. Have you tried lowering your multi to say 46 and seeing if you still get the problem?