Hey chelling, did you ever find a solution to your problem or hear back from Asus?
I have been having fits with mine and our problem sounds similar.
I have the 3600Mhz set of memory but if I set it to DOCP or manually set it to 3600Mhz my motherboard cycles a few times then boots in safe mode. If I up the DRAM voltage to 1.4 and set DIGI+Power Control->DRAM Current Capability to 120% it boots pretty much every time but it kinda annoys me that I can't set the voltage to 1.35 as listed on the base specs and get 3600 out of the set.
Anyway, if you have any suggestions I'd sure appreciate it.