Having similar issues here as well. Crashes mainly in dungeons, but once whilst in a city. Bumped it down to DX9 and issues persisted. It wasn't until I took everything off high/max settings that the crashes stopped. I've currently got it set to Standard(desktop) on DX9 and it hasn't crashed at all so far. I can play everything else maxed out but not FFXIV. However this never happened until my new GFX card. I originally used a GTX580 which was fine on DX11, however once I upgraded to a GTX1070 I started getting these crashes =/

If it helps, this is my setup :-

Win10 Home x64
i7-2600k at 4.5GHz stable
16GB RAM
GTX1070
Samsung 850 evo 250GB SSD
2TB HDD
ROG Maximus IV Extreme