my FC4 also crashes randomly with TDRs, all other games are running fine.
sometimes TDR after 5min in the game, sometimes i can play for hours.
 
i have two GTX 980 in SLI, tested both alone, and with both i get TDRs.
reduced core and vram clock, nothing helps.
 
the funny thing, NVIDIA devs can't repro
 
however at launch FC4 was working fine(first month), but now after tons of patches its unplayable for me because of the randomly driver crashes.
 
cya fc4... removed.
 
ps:GTA5 - 80 hours, no crashes at all.

I wouldn't worry about the Far Cry 4 Crashes. I've had the same problem as well with NVidia's new drivers (tdrs). Either use driver 344.75 or 345.20 to solve your far cry 4 crashes. I just played today, checking my overclocks on my watercooled evga gtx 980 (kraken g10 installed), and I got crashes also (after several hours as well). I was using the same overclock I had used with far cry 4 which had been stable for over 25 hours of gameplay using the 345.20 drivers. Driver 345.20 is simply the updated version of 344.75 which were released for far cry 4. Try it out and let us know how it goes wick. I've had good results with it. If anything, Ubisoft broke their game with one of their patches.
 
Sometimes, the best thing to do is play the game with the driver that was made for that game.