BIOS = UEFI effectively. I'm being technically correct (since it now no longer has a BIOS, as it's replaced by the EFI) but i guess it just confuses matters.
Anyway, if your RAM works fine and plays nice with the motherboard, set and forget, just ignore what I said.
However, if you set the start up the first time; set the RAM to its designated speed, load up the OS etc, turn the system off, then turn it on again (not a reboot, a complete shutdown) and find that it won't boot with the RAM light on the MB lit up - then you'll have to manually reset the RAM speed again in the EFI after pressing the small button on the MB. You'll have to do this EVERY time you do a cold boot in order for the RAM to work at its proper speed.
I'll run through what mine does to help explain I guess. (I have the same MB)
When I first turned on the computer and entered the EFI (BIOS), the RAM speed was automatically set to 1333MHz - this is the RAM's failsafe/compatibility mode. The RAM is rated to 1600MHz. So in the EFI, i set it up to use 1600 as the RAM speed, double checking it with the XMP profile. Save and exit, the computer reboots with the RAM working at 1600.
Ran benchmarks, applications, etc, no problems, fully stable, no issue. Reboot, it boots up fine, memory still running at 1600, stable under benches, etc. Nothing wrong. Once everything is working, I shut it down for the night.
The next morning, i turn it on and it does a double POST; it boots up briefly with the fans going for 3 seconds, shuts-down for 5 seconds, then starts up again, but the screen remains blank with with no POST information. When looking inside the case, a red light is on in the top right corner of the motherboard - indicating a memory error. The system will not cold boot with the RAM speed set to 1600.
In order to get the system to boot again, you have to press a small memtest button on the motherboard, near the light (it's shown in the manual). Hold it down and the system will reboot a couple times while it checks the RAM. When the system finally POSTS - it's with an error saying that the RAM has been reset, press F1 or something to enter setup. It'll load up the EFI and you'll see that the RAM has been reset to compatibility mode - in my case, 1333. It will do this little dance every time you cold boot with the RAM speed set 'incorrectly' (outside of it's compatibility).
I've just left my RAM at 1333 and it boots normally like any other machine. Reseting the memory to 1600 after faffing around with the EFI and poking around the MB for a little button every time i cold boot, it's just infuriating. I've updated the EFI several times with no success - it's just a known problem with certain varieties of RAM. From what I've gathered, it's mainly the older generation 1.65V DDR3 that causes problems and the newer 1.5V is more stable.
Anyway - if you set the RAM to it's rated speed (or it's set automatically for you), and there are no problems, just ignore what i said, you won't need to worry about this at all. However, if you set things up, then turn it on the following day and find it's not booting, just check the RAM light.
Oh, and another thing - don't bother using sleep mode in windows, the system will fail to boot, you'll have to reset the EFI to get it working again. It's a known issue with SB chipsets or something - i've tried it with this system, it chokes every time.
Now that i've scared you with a wall of text and issues you'll likely not encounter - lol - it's a fine motherboard otherwise. The ASUS software package is a little buggy though - and you have to use it in order to monitor the shit load of thermal sensors dotted over the motherboard, if you're interested in that sort of thing.
