Damian said:No, I think there's no way apart from obvious physical damage (card is up in smoke, GPU is melted) or obvious physical modifications (new heatsink, thermal paste).
That being said, I seriously hope you're not trying to RMA a card you killed by overclocking or because it didn't overclock enough.
I see he's selling 9 Radeons in the classifieds, maybe he's worried bout OTHER people sending him back damaged overclocked cards.
Overclocker550 said:its easy enough to make video cards that have a rom chip which writes on itself when you overclock it so when you return it, fried or not, they will know
snvpa said:I don't think it something a person could do manufacturers could sure do it, but as soon as they did someone would find away to flash the chip back to its original state. As far as your situatuation goes, not much you can really do but have faith in people.