You DRAM ratio could be stopping you. It's possible that your memory is set to 2:1 or something around those lines. You may need to drop it to a lower ratio, or up the RAM voltage. Good luck.
Edit: The longer version...
You ram mhz are based off of your CPU mhz, so if you have it set to 200 x 11, you have a 2200mhz cpu, but your ram is also 200 x (whatever ratio you have it set to, 2:1 = 400mhz, 3:1 = 600mhz, etc.)
So if you were to drop the ratio a little bit, the mhz of your ram goes down, but it may give you stability.