Hello! Thank you for playing Final Fantasy XIV!

I apologize that you are experiencing this! I would suggest lowering the graphics settings in-game, as the intense graphics in dungeons can cause the issue. 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.