Good morning and thank you for posting on the Final Fantasy XIV Technical Support Forums.

What exactly do you mean by the "DX mode toggle is only available when there is no driver at all?" Are you not able to select directx 9 mode on the launcher?

Make sure no other programs are running when you play the game and also check that your anti-virus/firewall have the appropriate exceptions for Final Fantasy XIV.

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