Nice, I was puzzled with a similar problem recently for my own built. It's best to check the reviews for the G.Skill RAM at Newegg to see what users reported.
I was between G.Skill and Corsair, finally went with Corsair because of compatibility issues that people were having.
The RAM initially ran at 1333MHz by default, but ASUS has a very convenient "RAM speed setting" in the BIOS. I configured it for 1600MHz, added the timings (CL9) and everything's working at 800MHz dual (i.e 1600MHz). The only thing that has always puzzled me is the fact that CPU-Z is reporting a bandwidth of 10700 (10.7GB/s) for some reason, depite the frequency actually being correct at 1600MHz. Oh well, as long as you know the speed you're running at, and can set your timings too you shouldn't worry about anything else.
So the only thing you'll have to set is the speed, which takes literally 5 seconds and a reboot.
*My built (partly)
ASUS M4A79XTD EVO
Corsair XMS3 1600MHz DDR3 PC12800
AMD Phenom II X4 955 BE