I have the Asus GTX 580, and wanted to set up 3 monitors for Microsoft Flight simulator. Trying to figure out my best option. I'm thinking a 2nd GTX 580 will do the trick, but they're sooo big. Considered going AMD route, but I've always used nVidia. Recommendations? 2nd 580 ($), or replace with GTX680 ($$$), or AMD card ($$)?