I do remember reading about that issue. Was supposed to effect the 8800GTS 320MB card and I assume the 8800GS/9600GSO. Same thing was supposed to happen to the 640MB GTS, but didn't because it had more memory.
What was the fix for it? I would say check for a newer bios for the card but flash that wrong and you have a paper weight. Perhaps try some other/older drivers?