The site Hardwareoverclock Austria has posted an article about performance analisys of a nVIDIA SLI system made by a Asus 7800 GTX 512 and a Gainward 7800 GTX 512.
The cards were tested with a dual-core cpu, the AMD Athlon X2 4800+. Using the latest game F.E.A.R. (it is in the following image)
with 1152x864 Maximum Quality, AA 4X and AF 16X settings, the scores were:
Normal: 41 min. / 102 Avg. / 270 max.
High Quality: 40 min. / 71 Avg / 171 max.