Thank you for the reply Elvishuy.

My first thought is that your GPU might be overheating. Do you have a way to check the temperatures?

As the above poster mentioned, you may want to try selecting DirectX 9 mode and see how the game reacts.

I'd also like you to double-check the Nvidia Control panel settings. In the Nvidia Control Panel, go to 'Manage 3D settings' and then to 'Program Settings.' Select Final Fantasy XIV here and scroll down to find the V-Sync setting. Turn it to 'Off'. This will force vertical sync off while in-game so if there is any setting that is artificially lowering the frame rate because of v-sync, this should turn it off.

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV!