I've played thru Warhead twice. First time I didnt enable crossfire, second time I did. There was a slight improvement with crossfire but it was mostly negligible... Only time I noticed the difference was during the last fight at the airport when alot was going on. Even with crossfire I got some slowdown but it wasnt as drastic as compared to when I was only using one video card, things got so bad then that I had to pause the game and drop some of the settings down....