GPU Crashes on two completely separate machines

Hiya

We have two PC's and they both consistently have the display driver crash and recover when playing FFXIV. They're different specs.. the commonality is they are both i7 Intel machines with Nvidea graphics; a GF780 and a GF680.

+ Using latest drivers and BIOS.
+ No Anti Virus.
+ Graphics Cards certainly not overheating.
+ No other game produces the issue; tried Battlefield 4 for example.
+ Cards not overclocked
+ CPUs not overclocked

The issue becomes more regular on higher settings but it is not repeatable by any kind of player action or event.