Benchmark Results: Aliens Vs. Predator
The first strike against AMD’s three-way scaling comes in Aliens vs. Predator, where overhead appears to make the triple-card configuration lose a little performance.
Multi-card scaling usually improves at higher resolutions and details, yet three-way CrossFireX still falls behind CrossFire using a pair of cards. It appears as though this title uses only two of AMD’s cards, and that might be a problem with Catalyst Application Profiles. Excellent scaling realized on Nvidia's three-way SLI setup adds insult to AMD’s injury.
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.