Hello! Thank you for playing Final Fantasy XIV!

We apologize for any inconvenience you may be experiencing. The crashing of Direct X may be caused by a variety of issue. We would suggest lowering the graphic settings in game, as the intense graphics in dungeons can cause the crashing. We also suggest that the graphics card are using the latest drivers for the card. Should you be using Direct X 11 and experiencing the issue, we would suggest reverting back to Direct X 9 to see if the issue still persists.

Thank you for posting in the Final Fantasy XIV Technical Support Forums.
Please let us know if your issue gets resolved and what resolved it, So we can further assist other players.