According to a post in the asus newsgroup, it is mentioned that the german mcomputer magazine ct are claiming that if the memory timing is set by spd, and the cycle chosen is 7T / 9T, the mobo will default to using 3-3-3 settings, and if the cycle is 5T / 7T it will default to 2-2-2 or it will hang if the highly oc'ed.
I haven't tried to test this claim out yet, but if you look around in the asus newsgroup you should be able to find it.