Question GPU Not Detected by MB

Aug 17, 2024
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I built my PC just over 2 years ago and it's been working great (specs below). However, a few days ago, I believe during a Windows update, the display stated it could no longer detect an input source. I have tried many things such as reseating the GPU, M2, and RAM. There was a faulty VGA power cable which I have since replaced, but the problem remains. I can successfully boot to Windows, but if the HDMI or DP cable is plugged into the GPU, I get a Q code on my MB "d6", which apparently indicates no GPU detected.

The PC works fine when I plug the display cables into the MB, after several attempts at reseating the GPU, my PC can no longer detect it. I have uninstalled the drivers but cannot reinstall them, as that requires the PC detecting the device in the first place, which it can no longer do.

So, I'm at a bit of a loss and would like to see if anyone has any further suggestions. Apologies, if I have left some information out, please let me know if there's anything else you need to know.

Thanks.

PC Specs
MB:
ASUS ROG Strix Z690-E Gaming WiFi 6E LGA 1700
CPU: Intel Core i9 12900KS 5.2 GHz
GPU: MSI GeForce RTX 3090 Ti SUPRIM X 24G
RAM: Corsair - 64 GB - 4 x 16 GB - DDR5-5200 (2600MHz)
PSU: EVGA Supernova 850 Gt Power Supply, 80 Plus Gold 850W, Fully Modular
 
Last edited:
Aug 17, 2024
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What is the make/model of your PSU? Have you verified that the PSU connections to both the 8-pin (2 of them) and 24-pin connectors are firmly attached?
Originally, the PSU 6+2-pin connectors for the GPU were dodgy, see attached image. However, after replacing this cable everything was working correctly. But after a couple of hours everything shut down and I've been having problems ever since. The new PSU cable is firmly connected according to the GPU's recommended installation.

I've updated the original to include the PSU specs.
 

COLGeek

Cybernaut
Moderator
How old is your PSU? The high-end 3000-series Nvidia GPUs are very picky and demanding in regards to PSUs.

I would not recommend using a 850W unit with the 3090 Ti. Rather, I would recommend you use a quality 1000W PSU.

Upload images to a site like imgur.com and then post a link here.
 
Aug 17, 2024
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How old is your PSU? The high-end 3000-series Nvidia GPUs are very picky and demanding in regards to PSUs.

I would not recommend using a 850W unit with the 3090 Ti. Rather, I would recommend you use a quality 1000W PSU.

Upload images to a site like imgur.com and then post a link here.
It was brand new when I bought it of course, so 2 years old now.

Is it really possible that it would work for so long and then not be able to cope on 850W?

Apologies, I forgot to upload the image: View: https://imgur.com/a/8eNSYoD
 
Aug 17, 2024
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I didn't think so, but just realised there is an old one in the garage. Giving it a try now! Thanks. I thought possibly the PCI-E slot could be damaged so hopefully this will rule that out.
Okay, I've plugged in my old GTX 1050 TI and it works. So, I suppose this rules out the PCI-E issue. I'll check if the PSU in my old PC is 1000W, if so, is it worth trying that to see if power is the culprit?

I guess this narrow the potential issue down to the following (correct me if I'm wrong here):
  • PSU Wattage
  • The GPU
  • The GPU has a special adapter as it uses a 12-pin power slot. The adapter can be difficult to plug in (there is some kind of physical resistance but nothing I can see). I suppose the adapter could also be limiting the power the GPU is receiving, if there is an issue with it.
Thanks for all your help so far.
 
Aug 17, 2024
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Seems we are down to PSU or GPU....or the GPU adapter (especially after seeing the pins in the picture earlier).

Start by verifying that the receiving pins on the adapter are in good shape. This could very well be the real issue.
All of the pins are visibly intact. But I don't think I have a spare adapter to test or any more 6+2-pin cables either. I can't tell what is causing the resistance. It's very strange. Sadly, the PSU in my old PC is only 650W so I'm gonna see if I can get my hands on a friend's one if that have one available. Don't really wanna buy one unless I'm sure that's the issue.

Any suggestions on narrowing this down further? Or is the only option to get my hands on another cable or part?