RAM will not run at rated speed

I have the

Corsiar DOMINATOR 12GB (3 x 4GB) DDR3 1600 Model CMP12GX3M3A1600C9

My Rig is:

ASUS Rampage iii Formula Motherboard
Intel i7 960 @ 3.2 GHz
12GB of Corsair Dominator RAM
EVGA GTX 570 HD 2.5GB


In Speccy my RAM says it's running at 534MHz. I think maybe I don't have the right combination of RAM / CPU to get it running at 1600. When I set it to 1600 in the bios or try to use the XMP which is advertised on the friggin' box, my PC will not boot. Also, in the bios I get a message about only being able to use RAM frequencies of 1066 or 1333MHz with this setup. it's like "For locked CPU ram will only run at 1066MHz or 1333MHz". Do I have to spend $1000 and get a 990X to run my ram at the rated speed?

Though I swore I saw a review of the Rampage iii Formula where they had the same i7 960 CPU and RAM and said they OC'ed the CPU and got the RAM running to the specified 1600MHz with no problems. Am I doing something wrong?