Help with dual video cards

I currently have a Nvidia Quadro FX 4500 installed (PCI-E) and I just installed a EVGA GeForce 8400 GS (PCI), however Windows 7 (Ultiamte 64Bit) doesn't detect the PCI card. When I go to the BIOS, it sees a video card in the PCI slot. I tried installing the drivers from the EVGA website and that still didn't do anything. I had was using a really old PCI video card before this and it worked (4 monitors) but I had some weird problems with it so I upgraded to the 8400. Any help would be greatly appreciated. Thanks in advance.

oberatixx, welcome to the forums.

Think you will find that what is happening is that you are trying to use a DX 9 card with a DX 10 card, and they don't both use the same driver in Windows 7. The DX 9 card (the Quadro) can only use the WDDM 1.0 driver, while the DX 10 card (the 8400) uses the WDDM 1.1,

Windows Display Driver Model - Wikipedia, the free encyclopedia

and despite there being some files from each that will be the same, there is still a conflict between them and one of the cards ends up disabled or not working properly. The problem is that they are both Nvidia cards and that is what is causing the conflict (same thing happens if two ATI cards that are DX 9 and DX 10), and doesn't happen if the other lower DX version card is a different make (Nvidia with ATI, etc) as despite the cards using a different WDDM they are also using totally different drivers.

P.S. You wouldn't be the first to run into this, there have been quite a few threads about this here (just couldn't tell you what search terms to use to find them).

stormy13 said:

oberatixx, welcome to the forums.

Think you will find that what is happening is that you are trying to use a DX 9 card with a DX 10 card, and they don't both use the same driver in Windows 7. The DX 9 card (the Quadro) can only use the WDDM 1.0 driver, while the DX 10 card (the 8400) uses the WDDM 1.1,

Windows Display Driver Model - Wikipedia, the free encyclopedia

and despite there being some files from each that will be the same, there is still a conflict between them and one of the cards ends up disabled or not working properly. The problem is that they are both Nvidia cards and that is what is causing the conflict (same thing happens if two ATI cards that are DX 9 and DX 10), and doesn't happen if the other lower DX version card is a different make (Nvidia with ATI, etc) as despite the cards using a different WDDM they are also using totally different drivers.

P.S. You wouldn't be the first to run into this, there have been quite a few threads about this here (just couldn't tell you what search terms to use to find them).

Is there anyway to get them to both work properly together?

Unfortunately not that I have seen. The only workarounds I have seen for a situation like yours is to either go back to XP where both will use the same driver, or get a different make of card (ATI with a cheap Nvidia, Nvidia with cheap ATI).

Hopefully someone else will have seen something, or been in the same situation and found a workaround.

This is what I was getting at,

One of the limitations of WDDM driver model version 1.0 is that it does not support multiple drivers in a multi-adapter, multi-monitor setup. If a multi-monitor system has more than one graphics adapter powering the monitors, both the adaptors must use the same WDDM driver. If more than one driver is used, Windows will disable one of them.[7]. WDDM 1.1 does not have this limitation.[8]

Windows Display Driver Model - Wikipedia, the free encyclopedia

which is what is happening in this case as the FX 4500 can only use WDDM 1.0 and is conflicting with the WDDM 1.1 compatible 8400. If the new card was anything from the 6xxx or 7xxxx series of cards there wouldn't be a problem. Same thing has happen to a few on here trying to run a WDDM 1.1 ATI card with a WDDM 1.0 ATI card. The one thing that I ahve seen that works is if one card is from Nvidia and one from ATI and work, even if both aren't WDDM 1.1 cards.