I have the some problem, sometimes the sli is not working, it just show fhysx in Nvidia controlpanel.
And i have 2 Gigabyte 460 gtx 1 gb oc cards and gigabyte mb GA-X58A-UD3R sli( and i have the power for it 800w)
It was working whit the 270.51 beta drivers and when i upgrade to 270.61 sli stop working.
I then find a small program called SLI patch 1.42 beta and now it works, but why do i have to use a 3:d party program to have it work?
Should it not work whit the drivers from Nvidia?
And i have the latest bios on the board ( FF) And Video bios: 70.04.13.00.01