PhoenixMiner not detect second GPU, CUDA not working with second GPU

[hiro_nagasumi]

Hello,

i try to run 2 RTX on PhoenixMiner 5c. The first GPU which is in the normal PCI16 GPU Port Phoenix miner detect. The Second GPU which is connected via Riser on a PCI1 Port PhonixMiner not detect.

I think the Problem is that the CUDA is not working with the second GPU, but i dont know why.

That the Stats of the first GPU:
http://gpuz.techpowerup.com/21/03/10/j2p.png

And the Second GPU.
http://gpuz.techpowerup.com/21/03/10/7ck.png

The second GPU CUDA is not checked. But why?

http://img4.imagetitan.com/img4/gCR92YAoKZ0uSoS/23/23_gpu1.png

Device manager shows no problems:
http://img4.imagetitan.com/img4/small/23/23_device_man.png

I tried to switch the GPUs but the Problem is still the same.

The Mainboard is an ASUS Prime X570-P and the power supplies is a BeQuiet with 850W. I Think thats enough for this 2 GPUs an the CPU.

Does anybody have an idea what could be the problem?

[th00ber]

Yep

Your  second card (http://gpuz.techpowerup.com/21/03/10/7ck.png)
GPU-Z seems to indicate that is not a CUDA device (CUDA is not checked)
You probably have a problem with your driver

[hiro_nagasumi]

Yes but when i switch the GPUs they said the same to the other GPU. So the Driver worked well. Only not for the second GPU.

I found just now in internet that CUDA is only activated if the HDMI Port is busy. So maybe i need an HDMI Dummy Plug first for the second GPU. I dont have a second Monitor or TV to check this, so i ordered a HDMI Dummy Plug and write when i test with the Plug.

[th00ber]

I had two nvidia cards for long time and neve had this problem.
Right now I ahve RTX 3090 and GTX 1070 Ti on the same desktop and everything is fine

I'm pretty sure it's only a probleme with driver or maybe your mobo slot

[hiro_nagasumi]

It works now. But it was not a problem with NVIDIA Driver. I installed the newes Chipset Driver for the Mainboard.

But it worked not normal. Its luck. The Mainboard has 3 PCIEX1 Slots.
On the First PCIEX1_1 the GPU is detect after each 2nd restart and with Version PCI-Express x1 3.0
On the PCIEX1_2 & PCIEX1_3 it worked maybe after 4-5th restart and then only with Version PCI-Express x1 1.1 (But the Riser support 3.0)

In the Bios the only settings for PCI ist SR-IOV.

Maybe there is a Problem with the Bus interface.