Mixed Nvidia cards under Vista

Hi.
I apologize profusely if this is covered somewhere else, but I wouldn't know what to search for in order to find if it is...
Ok. I have a custom machine with an evga 780i motherboard and an evga 8800gt. This works great. I just recently replaced my aging 6600 256MB card with the 8800, but I have recently come into the possession of a couple of extra monitors. What I thought would be really great is if I could put the 6600 in one of the other PCI-Express Slots and then I could have 4 monitors. Is that possible? I am pretty sure that the drivers for the 6600 are in the same package as the ones for the 8800 so I wouldn't think that would be so much of a problem. I just want to make sure before I end up hosing my machine.
Thanks,
ghostmachine

No reason it shouldn't work. If the card has some compatiblity issue it will just not work but there will be no risk to the hardware.

Just check your power supply is up for it.

Alright. I went ahead and tried it. When I put the card into the second PCI-E slot, I get a message at boot up telling me that for SLI I have to move it to slot 2. I guess the slots are ordered weird with 1 and 2 on the ends and 3 in the middle... Anyway I put it in slot 2, it boots alright, but then varying degrees into vista bootup I get a BSOD. The first time i got logged in and everything, then it bluescreened when it went to install the card. That was the last time I saw my wallpaper Now it bluescreens before it hits the logon screen every time. I can still get to safe mode, so I could use system restore since I made a restore point before I tried this . Is there anything else I could try? I would really like for this to work...

Somone will need to chip in here as now we are into someone with experience setting up dual cards and that is beyond me.

Just a thought, I do not think you want to set them up as SLI, as that is to boost performance for 1 display (using 2 cards) and I thought the intention was multiple displays.

If you can still boot with either display card I would be checking with one at a time to see if they have the latest bios update and the driver (I think you already did that) and updating if necessary.

It is. The board automatically tries to set up SLI. It was designed for tri-sli. I just like the extra features
I did already do BIOS updates on both the cards and my motherboard. I used the 6600 as my only video card for a good 3 or 4 years. I'm almost sure this should work, since in my little world it doesn't seem so different from having a discrete graphics card and leaving the onboard video enabled for a third (or second if your card sucks) monitor.

This now needs somebody more familiar with running the cards together to jump in and help if they can.

I can't yet offer an advice on this only my experiences so far. I have a Asus A8N-SLI mobo with a geforce 7600 and 7100 filling the pci-x slots. In XP these cards work together just fine letting me run up to 4 monitors without a problem. In Vista I end up with vista failing to boot, restarting and then offering to start in safe mode. If I boot to safe mode I am able to go to device manager, disable the 7100, restart and boot up fine with just 2 monitors. Once booted this way I can re-enable the 7100 and get all monitors working fine; however, when I restart the system I get the same garbage again requiring a trip to safe mode to disable the 7100 again.

I used to have OSX-x86 running on this same setup and had problems very similar to vista. However in OSX I had to actually pull the 7100 out to get it to boot, I wasn't able to find a way to disable the card.

Like I said I dont really have any insight into what the problem is here but every little bit helps I suppose.

I had 2 cards working great under XP. It was the aforementioned 6600 and a crappy old 8 meg PCI something or other. It worked without a hitch. I think the problem is with NVidia cards is for them to work right at all they have to be from the same series aka 8xxx 7xxx 9xxx whatever. Mine are 2 apart. Vista is just gay about the whole thing. It installed the drivers for the 6600 just fine without me having to do anything, so I know it already has drivers for it. That was from a fresh install too. Oh well... I have just about given up on the issue. I am now waiting to see how that program for encoding videos using your GPU works out. If it is all it's cracked up to be I may just SLI the 8800 and that will be the end of it.

[edit]
oh and here it is in case anybody cares...
hxxp://elementaltechnologies.com/how_it_works.php