Benchmark Results: Crysis
Though we use it primarily as a system-wide test, Crysis continues to show good performance scaling for different levels of single-GPU performance. SLI and CrossFire were fixed long ago, but what about three-way?
A third card appears to be about as appealing as an auxiliary nipple at 1680x1050, but higher resolutions prove the viability of both company's three-way solutions. AMD’s second card scales a little better than Nvidia’s, while Nvidia takes the scaling lead when a trio of boards run side-by-side.
Here's another article on the 68xx series in Xfire
Xfire scaling was found to be 100% on 10 or the 19 games they tested, and remaining very high on the others. Nvidia and ATi seems to trade blows at different games tested, but it is evident that Ati has stepped up their Xfire drivers int he 6xxx series.