I play on a PC. Since the last update I've had lots of PC reboots when playing the game for "no apparent reason". Checked drivers, checked forums, saw that others had the issue and started blaming FFXIV since that's the only time these reboots happened.

WELL -- I WAS WRONG. It was not DX11 or anything having to do with the game. Got sick of the reboots and decided to look inside the PC. Turns out the PC has choking to death - all of the fan screens were almost plugged with dust and junk. The fans themselves weren't much better. Cleaned it all up - no reboots or shutdowns since. So most likely during heavy play the internals were getting too hot and the system was shutting itself down.

Bottom line: I encourage everyone to check their fans for junk.