New Asus MOBO very picky about GPU and Booting

[No-One]

Hello all! I have built over ten PCs myself and I am assisting a close friend of mine after recently helping him build his first pc using the ASUS Z790 V AX Wifi motherboard. He has been having an issue ever since it was built, that when trying to boot the PC, the motherboard properly goes through all steps of POST, the fans and lights are active on the GPU at this point until it gets to VGA in which it tries to look for the GPU (connected to monitor by a tested HDMI cable) and then shortly after the fans stop spinning on the GPU completely and the PC doesn't POST. The PC will do this indefinitely once the fans on the GPU stop spinning so, the PC must be restarted and we attempt this process again and hope for a different outcome. Which, for about a month or two would work successfully. If the issue occurred, eventually it would POST as long as he kept trying to restart the PC it would eventually find the GPU. Recently, he tried doing this for well over 2 hours and hasn't been able to get the MOBO to boot. We tried, taking out one stick of memory, switching GPU PCIE slot, clearing CMOS, and then after clearing CMOS we tried to boot into the integrated graphics which it did get past the VGA step of the POST process however, the PC then showed a boot drive error (power led 4 seconds on and then 4 seconds off). This boot drive error was not present prior to clearing the CMOS, and used to be able to boot into the integrated graphics or GPU without ever having boot drive issues. BIOS was updated a month after having the PC and it didn't seem to make any difference (positive or negative). 

Specs:
CPU: Intel i9-12900k
MOBO: ASUS Z790-V Prime AX DDR5
GPU: Gigabyte GeForce RTX 3070 Eagle OC 8GB
PSU: Thermaltake 850W 80+ Gold
RAM: G. Skill Ripjaws DDR5-6000 16GB x2

There are two NVMe drives installed on the motherboard, both tested working from prior systems and on is the boot drive. System is currently running Windows 10.

Thanks in advance for your help!

[achugh]

Hi @No-One , you and your friend can try the following and see if these instructions help you move forward.

Regarding your GPU issue, have you tried to set the CSM in BIOS value to ENABLED? CSM stands for Compatibility Support Module. It is a configuration that will try extra things to find devices. You also mentioned that you tried moving the slot in which GFX Card is installed. Please make sure your GFX card is installed in the PCIe Slot closest to the CPU. This slot is sometimes also referred to as PEG in BIOS or documentation or online forums etc.

You have not mentioned what NVMe drives you are using and which slots they are installed into. Regarding the boot problem, you can try setting FAST BOOT to DISABLED and if you also have ASUS LOGO DISPLAY set that that to DISABLED as well. These two configuration should be in your BOOT CONFIGURATION section of the BOOT menu once you are in the ADVANCED mode of BIOS.

In EZ Mode of Bios you can easily search for any of them and that is much faster way to find and adjust these settings.

I hope this information helps you move forward towards resolving your issues. Good luck!

[No-One]

The GPU was originally in the slot below the one closest to the cpu, this asus board has 4 PCIe x16 slots. 3 of those slots run at PCIe 4.0, and then the top most slot closest to cpu is PCIe 5.0 with a metal reinforced slot. We originally had trouble fitting the gpu in the top most slot where we initially planned on installing the GPU so instead opted for the second top most slot which is still a PCIe 4.0 x16 slot. The problem had occurred in this slot, and then the last time we were debugging (just the other night when we had reset the CMOS and encountered the boot issue) we successfully moved the GPU to the top most slot running at PCIe 5.0. I have not checked the bios settings that you had mentioned, and will be sure to mention it to him the next time that he can get the PC to POST. Currently, because of the boot issue it isn't posting even on integrated graphics. I don't know why it isn't posting when the boot problem shouldn't be affecting the POST and should still allow us to get into the BIOS, but we currently are unable. Thanks a lot for the helpful advice! As I mentioned, I will relay this information and be sure to follow your instructions the next time it does successfully post.

[Jiaszzz_ROG]

Hello, @No-One 

When installing the GPU, we recommend referring to page 1-7 of the PRIME Z790-V AX user manual for installation instructions.

If necessary, please update the BIOS to the latest version 1661, released on July 10, 2024, and clear CMOS.
Meanwhile, the ROG forum is specifically for discussions related to the ROG or TUF gaming series products. 
If you have inquiries regarding non-gaming series motherboards, we recommend posting your discussion on Zentalk>Motherboard.

Thank you.