Half-Life 2
Half-Life 2's default mode is AFR, however I run it in SFR mode too, to show you the difference in average framerate between the two.AFR
A pair of 6600 GTs in AFR mode double the performance of a single board for the most part, the final performance in AFR mode shadowing that of a single 6800 GT.
The SLI 6600 GTs can't quite push average framerate above 60 seconds at 1600x1200, meaning the sweet spot for that combination is around 1280x1024 with 2AA and 8AF, extrapolating back towards 1024x768 with 4AA and 8AF.
SFR
In SFR mode the story is much the same. Higher performance overall from all three SLI combinations ending up with the 6600 GTs just that tiny bit faster than the single 6800 GT. NVIDIA's default render mode for Half-Life 2 in SLI seems somewhat odd, given SFR's higher performance with all SLI configurations.
