Might be a bug with the 7-10 driver.. maybe try the 7-9 driver?

I'm running a x1950 pro here with 512 meg, and was recently running one with only 256 meg, and both ran fine on the new driver.

Maybe use the ati driver removal utility, and then install the 7-10 fresh without any old junk sitting around?

Way too many people take way too many things way too seriously.