Adding my own issues. This is on a system running Windows 8.1 Update, DirectX 11, and an nVIDIA GTX 960 using Driver 368.39, though the crashes were experienced on earlier driver versions as well.

Crashes will occur during instance changes, and appear to be only when the client is in background or I have tabbed out. The game client runs in a Borderless Windowed fashion for maximum framerate.

Attached is an error report from the Windows Event Viewer, detailing what is apparently an access violation error.

Faulting application name: ffxiv_dx11.exe, version: 1.0.0.0, time stamp: 0x576835b3
Faulting module name: ffxiv_dx11.exe, version: 1.0.0.0, time stamp: 0x576835b3
Exception code: 0xc0000005
Fault offset: 0x0000000000ec02d9
Faulting process id: 0x20d4
Faulting application start time: 0x01d1ce98af3d1f64
Faulting application path: D:\_Games\SquareEnix\FINAL FANTASY XIV - A Realm Reborn\game\ffxiv_dx11.exe
Faulting module path: D:\_Games\SquareEnix\FINAL FANTASY XIV - A Realm Reborn\game\ffxiv_dx11.exe
Report Id: cc984ec5-3a8c-11e6-80bb-c03f0e41f0aa
Faulting package full name:
Faulting package-relative application ID: