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I have an nVidia Quadro NVS 450 installed in a Dell Optiron 380. Only DisplayPort #1 and DisplayPort #4 are detected by windows. The machine has a BIOS setting to automatically choose the primary video card, or to disable the primary when a PCI-e card is installed (which it is). Windows cannot see DisplayPort #2 and #3 no matter what I do. I have tried the Windows Drivers, latest nVidia Drivers - no dice.

I am assured that this video card cannot break in this way.

I'm plum out of ideas. I've tried reseating the video card. I've contacted Dell and they've remoted in and looked around - threw their arms up after two hours.

Any ideas?

I'm running Windows 7 64-bit. All four monitors are 1600x1200 Dell monitors.

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I have a similar problem. I use a Nvidia NVS 450 and it seems to recognise only monitors #1 and #4. #2 and #3 show in NVIDIA Control Panel as "not connected". CPU is hp X400 workstation Win7 Prof 64 bits –  user67519 Feb 14 '11 at 9:54
    
Ultimately, my problem was that the card was bad. Swapped out the card and voila! –  Erick Robertson Feb 16 '11 at 1:50
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3 Answers

Are you using DisplayPort to DVI converters? They need to be active adapters, or you can't run more than two simultaneously. This is true on 99% of hardware.

If you're using active adapters (or native DisplayPort) then I have no clue.

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Yes, I am using DisplayPort to DVI converters. Then I'm plugging those into DVI cables to the monitor. The converters are nVidia converters. –  Erick Robertson Dec 24 '10 at 0:52
    
Would this cause the #2 and #3 ports to not even be detectable to Windows? –  Erick Robertson Dec 24 '10 at 3:00
    
Yes, yes it would. This is your problem. EDIT: Try connecting ONLY to #2 or #3 and see what happens. ;) –  Shinrai Dec 24 '10 at 5:10
    
When I connect ONLY to #2 or #3, the monitors are not recognized. I don't even get a POST screen or anything. If I switch it back to #1 after boot, it shows. –  Erick Robertson Dec 24 '10 at 8:45
    
@Erick - Okay, that is slightly odd, but I don't have experience with this specific card. It may be that they've tied the specific ports that are working to the TMDS signaling on that card (which would probably bring the cost down a bit, and doing the outermost ones makes sense from a cabling standpoint). The real test would be trying actual DisplayPort on it, which should work unless the card itself is defective. (That is, of course, always still a possibility - but you'll still never get more than 2 passive DVI adapters to work.) –  Shinrai Dec 24 '10 at 15:26
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Get a new Video Card.

Ultimately, the video card was bad. This was true even though our IT team and Dell both said that the graphic card could not break in this manner.

I think the key here is that even if I tried to use port #2 alone it still would not display. Ports #2 and #3 were just dead no matter what I tried. If #2 and #3 worked if I only used those two, then the other answer would have been best.

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Absolutely bizarre failure, but I'm glad you got it resolved. –  Shinrai Feb 21 '11 at 18:56
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I had a similar issue. The card was installed on a Dell Optiplex 990 MT with a 250W PSU and only two of my LCDs were being detected. After much fiddling around, and evaluating the possibility of changing the power supply to a 450W, I was able to rectify the issue by using HDMI connectors instead of VGA. Apparently, the card encounters such problems converting digital into analog.

I would suggest using the provided converters with a DVI cable directly or a DVI - HDMI cable.

It has been smooth sailing for me since then and I didn't even have to change the power supply.

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I was using the provided converters. –  Erick Robertson Aug 2 '12 at 15:07
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