Optiplex Desktops

2 Bronze

Optiplex 390 - GeForce GT 720 1gb GDDR3 problem

Dear Everybody!

Please help me have an Optiplex 390 and a GeForce GT720 video card. The video card works on another PC, but I just can't bring it to life in Optiplex. The card is not detected by the installer when running the driver. I then check the BIOS to see if it is visible, but it doesn't appear there either. BIOS update already available, currently on version A14. Someone may have encountered such a problem, I can fix it or I can bury my video card.

Thanks for advance!

Replies (7)
5 Iridium

if you are still getting video from onboard video port when 720 card is installed in 390, that suggests 720 card is not detected.   go inside device manager to see if any adapter other than the integrated HD graphics is listed.  also try both legacy and UEFI boot option in bios.   if there is secure boot under Advanced boot option in bios, try turn it off (or on) to see if there is any change.

2 Bronze


I checked this and there is no trace of it in the device manager, so it seems like it absolutely doesn’t recognize it.

try to use a very simple video card such as HD6350 or HD6450 dell oem (mentioned in tech guide) to test the PCIex16 slot in 390.  


Geforce 7XX cards 710 720 730 745 that are X1 or X4 or X8 or X16 where pins are missing will cause this issue.

There is no work around you need an X16 card with ALL Pins.

Non working card vs working Card

This is a Known issue for 15 - 30 years now

WORKING Card.jpg

NON Working Card.jpg



Report Unresolved Customer Service Issues

I do not work for Dell. I too am a user.

The forum is primarily user to user, with Dell employees moderating
Contact USA Technical Support

Get Support on Twitter @DellCaresPro

Diagnostics & Tools

7 Thorium

If the Dell machine also has "on board" video , some of these old ones can be reluctant to detect the newly added dedicated video card. 

If you can't find the old threads, I can trying digging something up for you. IIRC, it's mainly messing with relevant BIOS options and maybe connecting monitor properly before powering on ... something like that. 

Registered Microsoft Partner and Apple Developer
- Like many of you, I can appreciate a good game-engine.
- I answer questions here, but I'm not a Dell employee.
- Consider giving posts you like a "thumbs-up"
- Posting models-numbers and software versions speeds trouble-shooting.
- Click "Accept as Solution" button on any post that answers your question best.
2 Bronze

Thank you for your answers! I get it, I'll try it with a simpler video card. I was able to get an ATI RADEON HD7470 1GB video card. I hope it will work, although as I looked at the PIN assignment, it looks the same as the GT 720, but it’s also true for the HD6450 recommended by the manufacturer.


This is my GT720 PIN assigment:



And this is the recommanded (HD6450)



it seems the same to me


if you mean the gold teeth, those are standard PCIex16 connectors.  that is just standard connector. all PCIex16 video card have it.  Since you said your gt720 worked in another pc but is not detected in 390, try the HD6450.  If that does not work either, your 390 somehow has the PCIex16 slot disabled (or less likely the slot is defective).  Carefully inspect your 390 x16 slot for any obvious deformity or debris/dirt in the slot.

in case you wonder whether gt 720 is compatible w 390, yes it is.  12 users have validated it.

Top Contributor
Latest Solutions