There was a similar thread yesterday, think it was said to put ffxi in admin mode. Right click the icon > properties > compatibility > privilage mode (Administrator - click the box and hit apply)
remember someone saying during beta too, if you start up in windowed mode and go to task manager while ffxiv is running, find the .exe for ffxiv and right click set its priority to highest will put some speed back into the game. i'll try and find links and post em for ya.
If thats any help for you at all
FFXI : Ryobi & Ryder Asura
FFXIV : Bracken Wood Gridania-Balmung