Not trying to be a fan of the HD4850 in crossfire configuration, but TH has named this configuration over some single cards such as gtx275 or 4890 http://www.tomshardware.com/reviews/best-graphics-card,2404-4.html. So I find it hard to believe that even though you have Xfire boards available that you didn't test the configuration. In this case, I find it incredible to believe your testing results, since they are contradicted by the same publication in previous testing http://www.tomshardware.com/reviews/radeon-geforce-comparison,2007-19.html. Thus, I discount your extensive testing and depend upon my own observations and testing with my X58 @ 3.6Ghz setup with crossfired HD4850's. It's been fluidly running FSX and HL2E2 amongst others, and therefore I believe my eyes not your "testing."