I used my OG Titan last night, played a couple hours, left the Buzzer circling mid-air all night, then played more in the morning, 11 hours total in FC4 continuous (in addition to 7.5 hours earlier.) The OG Titan has never turned in a TDR / CTD in the last 27 months I've owned it.
Popped in the Titan X (using 350.05 HotFix), and it lasted 30 minutes and crashed. I give up, I'm going to call up for a refund today (since nVidia store doesn't do RMA apparently.) I don't care why it doesn't work (driver vs card) -- it just doesn't work reliably.
Litwicki, I really think there is a small percentage of faulty cards on the market. The forums aren't overrun, so I don't think the problem manifests for all the cards. Just some of us "lucky" winners. This smells so much like the 560 / 560 Ti fiasco. In the end the cards were dubbed faulty (unsolvable TDRs and CTD).