If you're a 7800GT owner that's not ready to take the plunge and do a hardmod to raise the voltage on your video card, you can still raise it by using a simple BIOS update(softmod). NGOHQ has the file, and some forum discussion on the matter.
Be really, really careful when doing this mod though. Most of the time, even just overclocking your card can void the warranty, not to mention actually changing the BIOS. The reward is a faster card, but the potential risk is a broken card, so it's no small matter. We only recommend a mod like this for the enthusiast who knows what they're doing, and understands the risk. We also recommend keeping a close eye on your video card's core temperature if you choose to apply this mod. Instead of just firing up a game and forgetting you even did the mod, load up a stress test program like ATI tool, and monitor the temp for awhile.