Overclocking wasn't horrible, but significantly less than what I expected. I was only able to get up to 137mhz DDR (274mhz). At 140mhz it gave me a BSOD before loading, at 139mhz it crashed half way through loading, at 138mhz it loaded but crashed during the benchmark several times. Guess it's just not that good.
FULL STORY @ MIKHAILTECH (http://www.mikhailtech.com/articles/memory/mt256ddr/)