So I recently got a sapphire 7850 2gb for $170. Damn nice card, super cool. I was thinking about getting a second one to xfire it. But is it really worth it? Im using a 46 inch led TV as my monitor. I get some screen tearing in ultra high setting for Bioshock infinite. Would a second 7850 fix that or should I change the card out for a single 7950 or 7970?