Biostar tb 250-btc pro

I am using BIOSTAR TB 250-BTC PRO.
So far, I have made 10 12GPURIG with GTX1070.Everything is working fine.

This time, I tried to configure a 12 GPU RIG using AMD RX5700XT.
However, although it starts up to 10 GPUs, when the 11th is connected, the BIOS is not displayed.

I also changed the connection order and cables.
I tried replacing M / B, CPU, MEM, PSU, GPU, riser card, etc., but the status does not change.

No matter what I do, when I connect the 11th sheet, the screen does not appear, and there is no signal on the monitor.

Is there a BIOS setting for AMD or RX5700XT?

This is my first experience and I am in great trouble. Please give me some good advice.

I look forward to working with you.

Did you ever find a solution to this?

No. I haven’t found a solution and I’m running on 10 GPUs.
Do you know any way?

I figured it out yesterday.

-Boot into the motherboard bios
-Go right to Boot settings
-Scroll down to CSM support and set it to DISABLED
-Save and Exit
-Install remaining graphics cards

Thank you for your reply!
Did you recognize 12 GPUs in that setting?
Is it working properly on 12GPU?

Yeah. All 12 cards boot and the rig is more stable. I was able to push some of the OC setting higher on the original 10 cards.

Wow! It’s great!
Which GPU are you using?
I am 5700XT.

I have this board in a few different rigs.

1 @ 12 x 5700XT
6 @ 12 x Vega 56 and 64

I also tried it today and succeeded in recognizing 12 GPUs.
Thank you!