Identifying GOP support of a GPU BIOS

[michaDE]

Hello,

first time poster here, I would have liked to avoid posting, but unfortunately I reached the limits of my technical understanding.
I was wondering if anyone could explain me how I can identify wether a GPU Bios has GOP support or not.

The problem I am facing, is that my MSI Z390A Pro Motherboard works only in UEFI mode (Setting is called "Windows 10 WHQL Support") properly with 6 GPUs, which I am intending to do.
If "Windows 10 WHQL Support" is set to "CSM", max 4 GPUs are supported, else a message "System is running with Insufficient PCI Resources! PCI devices were set to disabled state! It is strongly recommended to Power Off the system and remove some PCI/PCI Express cards from the system!" is displayed.
So far so good. As I am planning to use this MB with 6 GPUs I have it running with UEFI obviously.
Now, after flashing BIOS of 3 different GPUS individually, (All RX 570s 8GB) (with the suggested BIOS from "Polaris ONE CLICK Bios"), with each of them I received after the restart of the PC the error message "there is no GOP support detected in this card".

When hitting F1, the "Windows 10 WHQL Support" is set to CSM and booting to Windows and Windows itself works fine. Also the modded BIOS GPU works fine (attached one of these modded ones) , just with the downside that under these conditions max 4 GPUs are supported.

As mentioned above, I tried it with 3 different GPUs (ASUS, Sapphire & Gigabyte).
I am surprised that none of the 3 flashed BIOSes have this GOP support enabled. Is there a way to find out if that is really the case and it is not a motherboard issue instead?
From GPU-Z I can at least say that the flashed BIOS supports UEFI, this should not be the issue:

Any hint in the right direction would be highly appreciated!

GPU: Gigabyte or Sapphire AMD RX 570 (8GB, modded or stock BIOS)
Driver Version: Adrenalin 20.12.1
OS: Windows 10 64-bit
Motherboard + BIOS: Z390-A PRO (MS-7B98) // Version bios: E7B98IMS.1A0
CPU: Intel Celeron G4900, 3.1GHZ, LGA1151
PSU: Corsair HX1200
RAM: Corsair Valueselect DDR4 2133Mhz

 

[ballyhoo]

Hello,

I have the same problem.

I have an ASRock X370 Pro4 Motherboard with a Ryzen 3 1200, 4GB RAM and 6x GeForce GTX 1660 SUPER.

Unfortunately my rig works only with 4 GPUs, when I try to use the fifth one it only displays as TU116 [GeForce GTX 1660 SUPER] with the error message "NVIDIA OC failed".
The problem is always with the PCIE5 and PCIE6 slots.

ASRock told me to disable CMS and activate Above 4G decoding, which I did, but then the rig will not start. Not even into the BIOS.
I then changed the card to a 1050TI and I could start then into the BIOS again.
So I think it has something to do with the UEFI/GOP of the cards.

I tried then to flash another VBIOS on the 1660 Super. The card is from Manli and they have no VBIOS for download, so I chose one from MSI.
It works, but still not able to boot into BIOS and as soon as I attach five cards, the rig will not boot.

Did you find a solution yet?

Greetings Christian