Recently, my GTX 260 has been doing horribly. It started around a week ago, while I was playing Left 4 Dead. At times, my framerate would drop to the 30s and 40s, where it should have been a constant 60+. I've noticed this is all of my more demanding games. The heat has also gone up. Usually, when playing Battlefield 2, my card goes to around 55C, but now it reaches 75C. My case has pretty good airflow, an NZXT Tempest. What could be the problem?
More aboutperformance overheating
Does your GTX260 have a cooling fan? Is it working?
Maybe your thermal goop has taken a poop Also, it could be other resources not shutting down or using your gpu. Do you fold? have you changed drivers? Anything? Added? Have you, or did you go into your case for anything? Knock something loose? etc
What could be the problem? ------------------------------------
Sounds like you nailed in the title of your post. Use GPU-Z to run a log of yout GPU temps and check what the max temps are. 75 C for a GTX 260 isn't bad and shouldn't the point that the GPU starts to flake out. That's usually around 85 C or higher.