I think you're on the right track.
After seeing the high fan speed on my 660TI OC stopped the crashes I turned down the clock speeds on it by -2 with EVGA precision and locked it there.
Reseated video card, cleaned all dust from it.
Next I will try lowering fan speed to see when it starts crashing again.
I also turned of all unneeded software in msconfig.
I did a clean install of the nvidia drivers but only installed the driver and physX software and nothing else.
Repaired BF4 in origin.
No crash for over 5 hours of straight game play.
I did all the above steps. It seemed to work for a couple of days, but not now.
It's never going to work, because they dont care!!
