I had trouble with my XFX GTX260-216 Black Edition that seems to be the same as what you describe. I ended up having to RMA it, which was easier then expected and "stepped up" to a GTX280 to replace it. IIRC they said it was memory corruption and failed their tests fairly quickly.
A long drawn out process of elimination, tried another card ect.
I looked for a memtest program like that but it was a seemingly random problem while gaming.
You could try underclocking it, it made mine a bit more stable but I couldn't put up with it being underclocked and still crashing occasionally when I had paid for a factory overclocked card.
Sign up for support on the xfx website, register your card and open a support ticket, they can help you through the process of trouble shooting and possibly RMA.
Sign up for support on the xfx website, register your card and open a support ticket, they can help you through the process of trouble shooting and possibly RMA.
The problem is I bought it off of someone else. I had the "registration" transferred to my email (ie. the guy who registered it gave me the account, and I merged it with my account that had a 9800GTX registered)
However, for some reason, the GTX260 disappeared and I no longer have it registered. Can I re-register the card?
Also, I'm not even 100% sure it's the card - could it be the memory or software/drivers?