i don't think any game can even remotely stress the card like msi kombuster or furmark. so there's no need to only rely on them for testing stablity. i always test the stablity of a gpu oc by running like 50-100 loops of crysis or crysis warhead benchmark. or just playing them for like more than an hour or so or running unigine heaven dx11 on max settings for same amount of time. (and ofcourse vertical sync off to ensure constant maximum load on gpu) because i think cry engine 2 is one of the most demanding game engines along with unigine engine. honestly if your oc can pass hours of playing crysis warhead without a problem i really doubt it becomes unstable in any other GAMING scenario. because as i learnt by now crysis is very sensitive to any kind of oc (cpu-ram-gpu...) and i doubt crysis 2 will be much different.