Oh hey, you helped me last time. Man I'm kinda dumb these days. What would flashing exactly do? I've never really done anything like that for my video card.
Flashing vidcards to increase clock speeds and voltage. Increased clock speeds = more performance. Increased voltage = Increased clock speeds.
Only problem is, if the flashing goes wrong, you're vidcard is useless. And you can't return it.
If you want to OC, just use Rivatuner or something similar to OC.