This is exactly the same issue that I am having.
Mobo: Gigabyte GA-Z68X-UD3-B3
CPU: I7 2600K
Video: Onboard
RAM: 8GB Mushkin Radioactive 1600mhz
1x Mushkin SSD
Corsair VX450 watt
Win 7 64bit
Build went great except for memory running at 1333mhz.
I activated XMP profile 1 and memory was running 1600mhz which is its native speed. No other overclocking at all in the BIOS.
System was running perfect for over a week. Turned it off one night and the next morning stuck in an infinite loop as you have described.
Boot 1 second OFF boot 10 secs brief view of post screen shows mem has gone back to 1333mhz then OFF boot 1 sec repeats forever.
I have tried everything to get this back out of the boot loop but to no avail. Reset CMOS, Left battery out for HOURS and no change.
Am I looking at an RMA here? I seriously cannot even get it to boot once.
Loads of people having similar issues but they seem to be able to recover by clearing CMOS and other little techniques.
Did you manage to fix yours?
Help please!!