2600K killed by ASUS IV Extreme RAM OC mode?

Hey guys, I've loved reading this forum for years, but I think this is the first time nobody has had my problem, so here goes:

I have an ASUS IV extreme running the 3.4Ghz 2600K and the 2x 4Gb Corsair Dominator 2000MHz RAM. I had been running the memory in the 1866MHz 'OC' mode, thinking nothing could possibly be wrong with using the RAM at a lower speed than it is rated, but after reading about the OC modes on the IV Extreme roasting sandy bridge CPUs, I'm definitely scared, cos now my rig won't even boot to BIOS for me to diagnose anything.

The computer was running fine today, but I left it alone for about 15 minutes, and when I came back, it had shut down. Now it will not start beyond a half-second blip, and power is maintained to the ROG lights through the failed startup. I tried disconnecting the power switch and one of the GPUs to go easy on the PSU, and the same thing happens, so the PSU doesn't seem to be the problem. I also tried switching/flashing the BIOS, and I get the same thing. After one failed start, the Mobo won't respond to the power switch inside or out unless I turn off and on the power supply, then it fails in the same way. PSU is the Corsair pro series HX1000 80+, which is supposed to be bulletproof. CPU temp during prime95 never pushed 50C, and it idled around 28, so this is not an overheating issue.

If anybody has the extreme and those 2000MHz dominators, would you mind looking up the RAM voltage for the 1866MHz OC mode? I'm praying for 1.5V but am ready for disappointment. Expensive disappointment.

Am I looking at a fried CPU, or did the PSU somehow crap out but is still able to power the Mobo and at least let it attempt to boot?  

Thanks for the read, and hopefully somebody has survived this or knows what's up...