This is an extention of the Technical Support Guide found here
Furmark will push your video card to its maximum temp, its a great way to quick test for stability problems too.
As with any other benchmark, make sure you close any other programs.
Set the "Standard sizes" to your screen's native/max resolution. The higher you set MSAA, the more you will stress the card, 4 or 8 is fine, set it to the max if you really want to push your card. Start after you have these settings right and pay very close attention to the temperatures, this program will shoot your temperatures through the roof so be very careful, especially if your video card is overclocked.
For a frame of reference, the gtx 470 and 480 should not get to 100c, most other cards should stay under 90c to be safe, but of course: the lower the better.
You need to let this test run for about 2 hours, the more the better, probably 4 hours maximum. Watch the screen for any kind of glitching or artifacting. It should look very smooth and fluid.
If you see problems and your video card is overclocked, you need to back down the overclock settings, if you do not know how to, post in the Performance/Overclocking section or contact DSO for specific help.
If you do not see any problems and the temperatures look fine, your video card should be ok. Furmark is not the best video stablility test, passing this test does not mean your video card is 100% stable, but it is a good way to troubleshoot.
Edited by !ender_ - 17 Sep 2010 at 6:13pm