Crossfire you get to use the multiple gpus together, so they are always faster is done with the right cards.
This is my card I put in just 2 months ago, and the free games where cool lol
http://www.newegg.com/Product/Product.aspx?Item=N82E16814202008Look at the specs and you will see mine is only slightly slower.
If I had the money I would have done it in crossfire. And it is a big price difference for only 100 mhz more speed on the gpu and memory.
Plays every game I have completely maxed out. I am also on a amd 8 core 4ghz cpu and have fast memory in my system as well, all 3 work together in order to play the games well.
Shane