Well all of that got RMA'd and replaced, though not always with D9 unfortunately. I'm 3 for 6 with RMAing D9 and getting D9 back. What could be the issue here if not voltage? I've checked it with a DMM so I know how to compensate, and I run a Dominator fan over them to keep the kits cool. As for your low clock test, the kit won't even boot with voltage set that low. Well, the problematic stick anyway, the other one is just fine.