thinking about upgrading my 6850 for bf4 and my friend just upgraded his and gave me his 6850. so was wondering should i save money and crossfire the 6850s or should i just buy a good single card like i was going to
If all the games you play can use xfire then you would need a single card almost twice as powerful to beat the xfire setup. If the game cant use xfire then you get single card performance.
I'd say stick to your plan of one beastly card. A 7950 or 7970 from Msi, Sapphire or Asus would likely serve you well. But you could still keep the other 2 cards and make a back up rig at a later date. It is good to have 2 computers in case one of them goes out of service for one reason or another.