How to fix GPU not detected error

Recently we came across a case where we kept getting “GPU not detected error” when we upgraded a PC with a brand new motherboard and one of the latest Intel CPU. The GPU error lights kept coming up when we started the PC and it refused to communicate with a fully working GPU.

To fix the issue, you need to have access to another computer so that you can download the latest BIOS from the manufacturer website (in our case, it is ASUS) and unzip the BIOS file into a USB memory stick.

Background

The brand new motherboard that we worked on was an ASUS TUF Z790 Plus D4, the CPU was an Intel i7-14700KF CPU and the GPU was an Nvidia Geforce RTX 2080.

We searched the Internet far and wide and visited many discussion forums but couldn’t find a solution. Though our perseverance and a bit of luck we managed to get it working. So we thought it would be good to share it to fellow IT professionals, system builders and enthusiasts. The solution is actually rather simple and straightforward once you know what to do. So here it is.

The setup

Here is a photo of the Asus TUF Z790 Plus D4 motherboard and a photo of how the components are put together in the case.

We installed the GPU into the PCIe 16X slot next to the CPU as recommended. It is the best place as the slot has a direct PCIe 16X connection to the CPU. It is also the best place in terms of space as we couldn’t fit the GPU into the PCIe 16X slot at the bottom of the motherboard due to space limitation. And of course it is the best place for cooling.

But when we started the PC, there was no picture on the screen and the GPU not detected error light came on.

Trying

We tested the RAM, GPU on another PC and they were working fine. We put another GPU into the primary PCIe 16X slot to isolate the issue, but it also didn’t work. We re-sitted the CPU, re-applied thermal paste, but it didn’t work.

 We couldn’t get the screen working as this is an Intel F series CPU which does not have a working build in GPU.

 We double-checked the supported CPU list and the Intel i7-14700KF is definitely on the supported CPU list.

https://www.asus.com/motherboards-components/motherboards/tuf-gaming/tuf-gaming-z790-plus-d4/helpdesk_qvl_cpu?model2Name=TUF-GAMING-Z790-PLUS-D4

Some suggested that motherboard or CPU was faulty.

The discovery

We have tried pretty much everything and we still couldn’t get it to work. There was only one thing left to do. It was to try the GPU on the bottom PCIe 16X slot. The GPU won't fit there naturally due to space restriction. It is the only thing we haven't tired yet.

So we lifted the motherboard out of case, connected everything up on the outside with the GPU sitting at the bottom PCIe 16X slot. We started the PC and voila, no more GPU error light and we were greeted by the usual ASUS start up screen!

We went to the BIOS by pressing the DEL key on the keyboard. The BIOS version that came with the motherboard was pretty old. It was the first release version 0411.

On a different computer, we went to the ASUS website to download the latest version of the BIOS (version 1402) and unzip the BIOS file into a USB memory stick. We plugin the USB memory stick to a USB on our new system and updated the BIOS. After about 10 minutes. It was done and the computer restarted okay. We went into the BIOS again to check the version and it was running the latest 1402.

BIOS download link:

https://www.asus.com/motherboards-components/motherboards/tuf-gaming/tuf-gaming-z790-plus-d4/helpdesk_bios?model2Name=TUF-GAMING-Z790-PLUS-D4

The moment of truth

We installed the GPU back to the primary PCIe 16X slot. We started the PC and everyone was holding his/her breath. Not long we were greeted by the ASUS BIOS screen and everything seems to be working fine.

So we suspect that the BIOS that came with the motherboard was so old that there was some compatibility issue between the CPU and the GPU. When we installed the GPU to the bottom PCIe 16X slot, it was connecting through the Z790 chipset and somehow it was okay.

The solution should apply to other motherboards too. Have you come across a similar issue before? Did you do anything differently?

We hope you find this article useful. Please feel free to LIKE, SHARE and COMMENT.

More info

Manual download page:

https://www.asus.com/motherboards-components/motherboards/tuf-gaming/tuf-gaming-z790-plus-d4/helpdesk_manual?model2Name=TUF-GAMING-Z790-PLUS-D4