The GTX295 has a healthy history of being a very sick card. Sick as in illness. The damn things burn up left and right. My suggestion to you from all the research I've done on the GTX295's is to down clock the core, shaders and memory. The core by 50Mhz, the shaders you can leave alone at first, and the memory by 50Mhz. Set the fan speed to at least 80%, higher if you can stand it. Save it as a profile and use it for Folding. Have another profile for gaming and put the card to factory speeds, and yet another profile for desktop work. I call it desktop work because browsing the web, doing PowerPoint, reading PDF's, all that shit doesn't need the card running full speed.
So I down clock the cards as much as I can and it be stable. Down clocking can cause instability too. So I always find the down clock limit and go up by 25MHz. This is why my GPU's last so long. It's a PITA at first because you have to get into the habit of doing this stuff. But in the end, it protects your cards. Not long ago, my GTX280 went tits up. I had gone out of town and left it in Profile 4. That's for benchmarking and every other week, I would run it at that speed for a couple of days of Folding. But I left for a week and when I got back, the card had burned up. My fault because everything else was turned way down via my fan controller on that computer. That's why I use EVGA though.
Hell, I do that on my GTX280 and both of the GTX285's. Once you get in the habit of it, and don't forget shit, your cards last and last because of the low temps. I always pull the factory heatsink off and put on some Noctua NT-H1
for the GPU core, but I leave the pads alone for the voltage regulators, memory and so on. You can lower temps by 7-8Â° on some cards by doing that and as long as you don't damage anything, it's still covered warranty wise because EVGA is good like that.