Well it's not playing City of Heros good at the mo either (serious lag, black square,) but if I overclock my other hardware i.e. CPU maybe even my Ram would that have effect on overclocking my 6800gt?
I'll have to back up, it was running nice at the halfway point between 6800gt and 6800 ultra (387/1004) resulting in an extra 400score in 3DMark05.