Hi, I recently got a Mac Pro its a 2006 model, and I want it to work with my 27" Apple Cinema Display. It requires a Mini Displayport, which my 2006 Mac Pro doesn't have, and I'm looking to upgrade the graphic card, please anyone can guide me to which graphic cards are compatible? I want something with 2GB and up, or even a 1GB. Sorry I'm entirely new to graphic cards. Thanks!