When I replaced SuSE linux with Ubuntu 12.04 and then installed the nvidia driver, I was able to get SLI to work. However, I upgraded to 12.10 yesterday, and to my dismay SLI stopped working.
My LSPCI is as follows:
02:00.0 VGA compatible controller: NVIDIA Corporation C77 [nForce 750a SLI] (rev a2)
03:00.0 VGA compatible controller: NVIDIA Corporation GT200 [GeForce GTX 260] (rev a1)
04:00.0 VGA compatible controller: NVIDIA Corporation GT200 [GeForce GTX 260] (rev a1)
However, in nvidia-settings, I see that the 750a has somehow shoehorn itself in as GPU-1, between GPU-0 and GPU-2, which are the GTX260s.
In Ubuntu 12.04, it didn't exhibit this behavior. Instead, it managed to set up the two GTX260s as GPU-0 and GPU-1 respectively, and finally the 750a as GPU-2.
I'm interested to know if there is a way I can force the 12.04 nvidia drivers enumeration method onto the driver and make the 750a GPU-2 again. I noticed that the driver will only activate SLI if the two GPUs are enumerated in sequence before the 750a.