crossfire / sli is a solution to premote the performance of video-subsystem. But anyhow, i raise a concern about the doubled cost. and further on, the benefit of a crossfire or sli system vs. single carded system. 1/with doubled input, how much more can we get in pecentage? 2/the benefit of crossfire/sli is based on the supportance of specific software. there might be much promotion through testing softwares. but during daily appliance, can we gain that promotion? eg. when i play WOW, can i benefit from cf./sli?