is there any way that i could make this xfx 6800gt agp overclock higher than 400/1100 without increase vcore??? it auto detects at 400/1100 if i go any higher than aquamark freezes along any other game. i have seen some 6800gts with 420/1100, i saw an evga with 420/1200. how the hell do they do that??? i am using the stock cooler right now.