I am OC'ing my GTX 560 Ti 448 cores and stressing it with FurMark. I was just curious as to when I know when the card is stable, because I OC'ed it to 900mHz and stressed it and it came out fine so I ran it again, and my graphics drivers crashed. How many time should I run FurMark to ensure stability?
A one and done is not usually a good method to prove stability , in overclocking any component you do want to make sure that you have a completely stable part and that means rigorous testing. You certianly don't want to think that your stable and then start playing a game and then your crashing.
I would try a different software for testing and FutureMark has a suite of tests that can run your components through some tests. 3D Mark would be good to start with and it's free but you can also buy the upgraded version.
Furmark is the best but it has unrealistic loads but really tests the stability of the cards. You also need to let it run for a few hours, i would just open up and play different games and see if one crashes. I played a lot of BF3 and found my card to be unstable so i bumped the voltage another notch.