Alas, I tried 300/300 and quickly got a BSOD with an ati driver .sys file as the culprit. Maybe my core can't handle 300, perhaps the memory can, will try later.
In an unhappier note, a 3dmark torture loop that I ran overnight has quit to desktop (and kept the same res as the game tests, not my normal desktop res). Obviously something's wrong, so my question is is it the overclock of the system or the video card? I figure if it was the CPU or memory it would be a BSOD or reboot, but this was a crash to desktop so I'm *hoping* it was the vid card.
Still, even if it was, it's a bit discouraging. Oh well back to the mad scientist lab....