If you have two different bios versions of the same vendor or two cards from different vendor, make sure you update both cards to match firmware/bios rev. It fixes slugish performance in Crysis when SLI is enabled
and other games.
It runs better then ever. I updated my eVga 8800GTX to Rev 10 released on December 27, 2007. It magically fixed SLI problems with Crysis. It runs as Nvidia advertised with 169.28...happy gaming.