I am building a pc, I have a budget of around $800 for the graphics card. This is enough to buy two hd7970s and put them in Xfire, but is the Xfire worth the extra 400 I would pay for the second graphics card? I am looking for an amd card as I plan on playing some games in 3D, and to play nvidia in 3D you need $150 glasses. So, should I get 2x7970, wait for 7990 price drop, or just save some money and get 1x 7970. I plan on playing games like crysis 3 at 50-80 fps min on max settings possible.