So there is a sweet spot for vMEM as well:

At EXACTLY 1.075v I am rock stable at 1200mhz. Any higher or lower, and I cannot be stable. So the ram is capable, you just have to find the right voltage. Stability is checked by 1 hour Furmark, 6 loops of crysis benchmar, then 3 loops of 3dmark06. If no artifacts, I'm stable.

Also, it gets really hot at 1200mhz. I have some beefy heatsinks on it, and they still get pretty hot.