I've purchased a X79 extreme 7 around a month ago and pairing it up with the 3930k. Been playing around with it for the last two weeks or so and has discovered the following issue. When the system is OCed above 4800mhz, it would fail to get pass Window splash screen on cold boot, almost 9 out of 10 times. Even if I could successfully boot into windows on cold boots, the cpu speed were not up to par (down to 1200mhz under CPU-Z), and cpu temp registered @ 91C (with realtemp), across all cores. To get around this issue, I have to go into bios 2 times, or until the cpu temp reads above 30C within BIOS. Stability wise, I had test variable speeds, from 4.6-5.0Ghz, and they are all good under prime95 for at least 24hrs. My first assumption to this problem is cold bug/cold boot bug, as my system is under water. But wouldn't it be too high with an ambient of 17C?

X79 Extreme 7 cold boot issue-120205192851-jpg

CPU Temp read above 30C (in this case 45.5C, warm boot) start OK and speed start @ 5.0Ghz in windows
Temp usually started below 30C in this screen on cold boots, system refused to go pass splash screen.

I've read similar issues on some MSI and Asus boards, which all been fixed with BIOS updates. However I yet received a response from Asrock in regard to this problem, dispite sending 2 tickets to their tech support last week. For those who wonder what I did during my troubleshooting, here it is..

1)Re-sit Cpu and waterblock
2)Test system using a)4x4GB G Skill Ripjaws Z 1600 9 9 9 24 quad set @ 1.5v. b) Same Ripjaws set but 2x4GB only @ 1300mhz @ 1.5v c) 2x4GB Mushkin Enhance 996997 2133 9 11 10 28 @ 1.65v
3)Test system on a) Seasonic X-760, b) Enermax Infiniti 720W and c) Corsair AX850
4)Swap GPU from 1 slot to the other, tried both GTX580 and 4870x2 under Gen2, one card at a time, no SLI nor X-fired.

System Spec:
Windows 7 Ulitmate 64bit
Board:Asrock X79 Extreme 7
RAM:G Skill Ripjaws Z 1600 quad kits
PSU: AX 850
Cooling: MCP 655 + 560GTX rad + EK HF block