the618,
Memory quality aside, I think o/c'ing with the IS7 needs to be done in stages. Previously, I have tried running tweaked settings ie o/c's CPU settings + tweaked DDR settings all at one go. It didn't work for me. No o/c even beyond 2.4!
Then, I've tried setting the CPU speed first, finding the most stable speed. I've reached 290 yesterday, but crashed upon running 3DMark2001. I've set it to a conservative 270 and it ran like a dream @ 3244 MHz... just a little hotter on UT2003.
After that, I've started playing with the DDR settings. With the latest 1.3 BIOS, I have my DDR @ 1.65v, 2-3-3-6, Street Racer mode, Refresh Cycle rates set to 'Strengthened'. That is my most stable settings. PSB strapped to 800 @ 3:2. CPU is running at 1.575v.
All I need now is a good HSF to push my CPU a little further than 3.24.
I'm not sure if you have tried doing this yet , but I hope this could be of some assistance