My second gtx 260 came in yesterday, so I got to work setting it up. I used the SLI ribbon bridge to connect them and ensured I had a good connection from the PSU (Corsair 750w). It took me a few tries of uninstalling the drivers and reinstalling the updated versions to finally get the "Your system is SLI capable" pop up message, but when I go it I went ahead an enabled SLI.
I tested it out (although I'm sure I haven't really configured it to its fullest potential) on a few games, and all seemed to be working fine. I turned the computer off for a little while, came back and booted it back up, and things were still fine. I turned it off again after a while to go watch a movie. Came back to play it later that night, and suddenly there was something wrong.
I came to a screen that gave me the option to start Windows normally, or start up Windows in some sort of repair mode. I tried to start it normally a few times, each of which just went through the typical screens (memory test screen and whatnot), then instead of coming the the Windows 7 log in screen would reset back to the first screen. Eventually it came to a blue screen with a warning. It advised me to uninstall any recent software or hardware I had recently installed.
I tried rebooting and this time chose to start Windows in that repair mode. It ended up "restoring" Windows back to the last known working state. Started up fine, but I was curious to know what was changed. I went to the Nvidia control panel, and my SLI option was gone.
What could be going wrong? In another post of mine it was established that I had already had slightly above average temperatures. Could the extra GPU have increased temps so much that Windows would do this? Also, my PSU is only 750w. Is that sufficient power for SLI? It was working fine, then it wasn't.
Any help would be greatly appreciated.