Alright, so I am running 2x 8800gt's (evga) and seem to be having some issues.
Originally I was running 1 8800gt and loved it so decided to get another to SLI (using a 780i for a mobo) and went from being able to run 7 accounts of a video game I play (shadowbane) to 4- then hardlocking and having to restart my computer when I had both GPU's installed. So I popped one out and back to 7 boxes again. In messing with the SLI setting I made sure that in the NVIDIA control panel it was set to single-gpu because shadowbane is a pretty old game and doesn't support SLI.
Still having the same problem- open 4 boxes, one locks up when windows goes to end it my computer hardlocks and won't come out of it.
To my knowledge all my drivers are up to date, SLI is properly enable- though I did read something that stated Vista may say "single-gpu" is running and it's actually running in SLI mode.
One strange thing I noticed (and my computer knowledge is not very extensive) is that in my nvidia control panel one of the 8800gt's is give the IRQ of 16 and the other 0 - I'm not sure if this is correct- wasn't able to find much about it trolling google for about 20 minutes...
Okay, so I reinstalled the drivers, made sure it was set to single-gpu mode in the nvidia control panel and gave everything another whirl.
Started up the programs and got everything going- then bam- same problem, only this time instead of trying to close the frozen client I just let it sit there- eventually the character associated with the client was logged out of the game- within seconds of this happening my monitor gave me a nice "no signal" sign- despite my computer still being on (lights and fans all working). I tested my computer using 3dmark to see how things looked and I get back 56000 ratings which makes me assume that all SLI issues are clear.
So- think its a problem with the game I'm trying to play?
Also- I don't think its a PSU problem- all the power calculators I've used have put me under 450 watts and I'm using a 650w antec neopower.