I am experiencing exactly the same problem here, can we get some help ? Been trying to fix it for almost a month now.
MOBO: Gigabyte P67A-UD5 with latest BIOS - F6D (F6 is out, havent tested it yet). Flashed with the proper version of @BIOS w/o any problems. Both main bios and back up bios.
CPU: i7 2600K
RAM: G.SKILL Pi Series 2133mhz 7-10-7-27 1.65v
PSU: SilverStone Olympia OP750 - 60A on the 12V line...
I have tested the memory with memtest for about 1 hour and no errors. The system is rock solid once i manage to boot in Windows all day long. But as soon as i shut it down and boot up later on, it gives me the message where the clocks have failed and reverts the memory back to 1333mhz. At this point the bios remembered my settings so all i have to do is hit SAVE and EXIT and than it loads at 2133mz fine. But why is it having a problem when i power down the system and boot up later ? Its extremely annoying. Thera are at least 2 more people from other foprums tha ti know of and who have this problem so it is not an isolated issue. I feel the motherboard "testing" scripts on boot up are extremely sensitive due to the DUAL bios deal. This needs to change, i have been having the mobo for about a month now from BIOS F3 all the way to F6D i still have the problem.
If i leave the memory on AUto - 1333mhz, there is no problem and it boots up fine after i power it down. Even at 4.9 ghz CPU and it is stable. Only when i change the RAM settings it reports the "overclock failed" issues and than i have to go in bios again and SAVE and EXIT. I tried setting the ram to 1866mhz but i still get ths issue. I tried even 1600Mhz, the same issue. I tried QPI/VTT up to 1.2v, no help it still says overclcoks failed after a shut down and boot up later. At the same time, the system is perfectly stable at 2133mhz 7-10-7-27 1.65v 4.9Ghz CPU. Ran Prime 95 for 4 hours to test out the CPU, memtes for 1 hour, Lin X with latest libraries - everything registers stable but it will double boot after i shut down and it will report failed clocks for some reason.