Last night I tried under clocking to 722mhz from default 742mhz. It didn't crash for the 50 minutes or so I played with it, but my frame rate became jittery in Witcher 2, including strange stutters in combat. Also trying out Mirror's Edge there was bad performance over all and some severe drops in frame, probably due to asset loading.
Also, I learned that the strange glitches from Crysis 2 are known to occur on the one particular level I was on... So yeah, pretty much convinced that the first card was in working condition from the start.
So, this morning I found an old 200GB 7200rpm drive. Unplugged my C:\ drive, a 64gb SATAIII SSD, and put this one instead and installed Win7 onto it. After some updates I ran Witcher 2 and it ran great and didn't crash in the 30 minutes or so I played of it.
So, I decided that someone deep down in the inner workings of my OS were gummed up. Problems with DirectX. Problems with drivers. Problems all around. I've installed a few too many strange utilities to call the system inherently reliable. So I made a system image of my C:\ drive and formatted it. Now I'm on a fresh new OS and Witcher 2 ran just fine with stock clock, voltage, and my CPU overclocked to my usual 3.52Ghz. But in Witcher 2 I did notice some slow-down in combat... that may be a game-only issue. I'll play some other games to test the system, but I think I may be in the clear now.
Card runs pretty cool, as well. Using some special settings I can keep the card pretty quiet and cool, hovering around 52°C during Witcher 2. Maxing at around 56°C, and idling at 41°C.
Kindle Reading List (163,457 Locations Completed)
Finished: Aquariums of Pyongyang (2535), Under the Loving Care of the Fatherly Leader (24,074), The Lone Samurai (4753), Nothing to Envy (5349), Shogun (26,263), Eating with the Enemy (9170), Fight Club (3218), River Town (7524), Don Quixote (21,430), The Party(6492), Bravo Two Zero (7340), Rogue Warrior (7602), Mao's Great Famine (11,059), His Dark Materials Omnibus (20,766), Moon Lander (5882)
King Rat (9308)