Having purchased the same card as Ranulf here (since I linked it to him o_o) I've been having naturally similar issues, albeit since the recent patch they've been different by a bit. Before my crashing was centered around FFXIV--I could run [insert game here] for hours on end and never once have a problem. Some days I can do the same with FFXIV. Other days I can barely re-log after a crash before I crash again.

Temperatures within range of 40~50 C, tested at both full load (pushing the system also to 60~70 C) and with just XIV. We've tried varying drivers, time of day, cleaning out the PC, resetting configurations, so forth. All I can think of right now is either:

A) A direct look at the problem between NVIDIA and SE could fix it, though from experience in Q&A that would be a tremendous amount of man hours spent for something that might not be a huge deal in the grand scheme of things.

2) The card is bad and we ought to RMA as has been suggested.