Well this weekend I decided to overclock my gtx 680 lightning. My settings are : 93mv core voltage, 100mv memory voltage, 50mv aux voltage, 300 power limit, 160mhz core clock offset, 520mhz memory clock mhz with a custom fan curve that never went above 70c except when I used Furmark it went to 75 then I started to see things on my screen and then the card downclocked everything down and it was like at 600mhz core even after I started another unigine run. So I closed everything, did a reboot and now its working fine but I have this feeling that I've somehow ruined my card. I played Starcraft 2 on the highest settings and everything was fine no artifacts or crashes but after that I decided to read some articles on cnet and the screen would become blurred for like 3-4 seconds then come back to normal. What do you guys suggest that I do to check if my card is 100% functional or not ? I am using the ln2 bios, 301.42 nvidia drivers.