You can overclock a factory overclocked card. However, you should not plan to see much higher speed numbers than the people that have stock clocked card and overclock it.
Try EVGA precision. That should let you overclock it.
My card was stock at 590/999/1296. And so far ive found that i can get it to 722/1099/1585 stable. The clock and shader are pretty much at its highest there and the memory i havent finish testing but all seems well
would evga tool work with my bfg card lol? ive gotten rivatuner to work since this thread thanks tho.