Yay! BFG 7800GS OC.
Tested core all the way to 500, BUT past 470mhz at all and I get instant-reboots in fullscreen games. That's no good, and probably not healthy either.
Tested up to 1540mhz on memory, but once the heat builds up yellow dots start appearing. I'm not comfortable running it closer to that, though could probably pull 1530mhz if needed.