For example at 1920x1200, which was the resolution that we focused on, adding a second Radeon HD 5770 graphics card improved performance by 75% when testing with Aliens vs. Predator, while we saw a 78% performance increase when testing with Battlefield Bad Company 2. Other new games such as Just Cause 2 and Metro 2033 saw 63% and 86% performance gains respectively.



Link: Legion Hardware