Optiplex 7040 not detecting discrete gpu

[Jobble_Gobble]

Kia Ora, Hello,

 

I have recently purchased a Dell Optiplex 7040 from a PC recycler and I want to add a discrete GPU. I consider myself to be very much a beginner when it comes to this stuff but I have attempted a great number of things and cannot get the system to even register a PCIe device. I have tried basic troubleshooting such as removing the CMOS battery, updating the BIOS, enabling legacy boot mode, and following the steps provided in this article.

 

I have also tried swapping the slot the card uses as well as installing a network card in all of the slots to verify they work. Lo and behold the network card is detected fine and drivers are automatically installed on boot. As soon as I change that to a discrete GPU, the system no longer displays any device in the used PCIe slot. This is in both device manager and the BIOS.

 

As far as I can tell in my limited capacity the BIOS or maybe the Win10 install has some setting that doesn't check for a GPU or something. I should also mention as it may pertain to this matter. The GPU is driven by an external power supply separate of the proprietary one supplied with the PC as that didn't have any 6 pins. This PSU is 500W and exclusively runs the GPU. I wasn't sure if this was the cause of the issue but the gentleman who sold me the PSU and GPU assured me it wasn't.

 

The system specs are as follows:

i5 6500

Win10 Pro

16gb Gskill Ripjaws DDR4 

Radeon HD 5770

BIOS v1.8.1

 

Any help on this matter would be immensely appreciated.

 

Nga Mihi, Regards,

Jacob

[Bombastinator]

Does the 6500 need auxiliary power cables?  Most do.  There are a few exceptions.  Generally at the low end.  The 6400 and the 1650 don’t need them.  3050 too irrc.  Old dells are the bread and butter of those cards because often Dell PSUs don’t have extra cables.

Edited June 30, 2023 by Bombastinator

[GorujoCY]

2 hours ago, Bombastinator said:

Does the 6500 need auxiliary power cables?  Most do.  There are a few exceptions.  Generally at the low end.  The 6400 and the 1650 don’t need them.  3050 too irrc.  Old dells are the bread and butter of those cards because often Dell PSUs don’t have extra cables.

yes rx 6500 if that's what you mean needs PCIe power connector, 3050 too, all other cards like 6400 and 1650 do not

though for op if the PSU has a 6 pin, a cheap rx 570 would sound like a better solution, especially with the 8 gigs of vram (if you need for modern Triple A gaming at 1080p), one of the possible problems of the card is a vbios issue or a card issue (one diagnosis is trying all the displayport or HDMI ports or other display out ports where available)

[Jobble_Gobble]

32 minutes ago, GorujoCY said:

yes rx 6500 if that's what you mean needs PCIe power connector, 3050 too, all other cards like 6400 and 1650 do not

though for op if the PSU has a 6 pin, a cheap rx 570 would sound like a better solution, especially with the 8 gigs of vram (if you need for modern Triple A gaming at 1080p), one of the possible problems of the card is a vbios issue or a card issue (one diagnosis is trying all the displayport or HDMI ports or other display out ports where available)

Thanks so much for the response! The RX 570 would be a great option but unfortunately, I live in New Zealand where there isn't much like that on the second-hand market. I should have mentioned I had the 5770 verified in front of me in a different system. I don't currently have any DisplayPort or DVI cables to test with but I'll definitely grab some and give it a shot, thanks very much for the advice

[Jobble_Gobble]

2 hours ago, Bombastinator said:

Does the 6500 need auxiliary power cables?  Most do.  There are a few exceptions.  Generally at the low end.  The 6400 and the 1650 don’t need them.  3050 too irrc.  Old dells are the bread and butter of those cards because often Dell PSUs don’t have extra cables.

I really appreciate your response! I'm unsure if you mean the i5 6500 or RX6500. The CPU uses a weird proprietary connecter along with the MOBO and exactly as you say the PSU doesn't include any other cables, hence the second power supply dedicated to the GPU (Currently the intention is to tape it to the top of the PC). Unfortunately, where I live in NZ the second-hand market is really small, and cards like that are either overpriced or just nowhere to be found.