Problem : Motherboard Z390 does not start with Riser - Help

[Oraklos]

I am stuck in the RIG construction.
When I plug the GPU directly on motherboard, the system boot perfectly.
When I use a riser, the system does not boot (i can't even access to the bios). The fans of the GPU are correctly working.
I can access to the bios but juste after bios, the boot is frozen, i do not even have ubuntu starting

I spend time checking every seting in the bios but do not find anything obvious.

MB : MPG Z390
riser : https://images-na.ssl-images-amazon.com/images/I/81A0nbQZyuL._AC_SL1200_.jpg
GPU : RTX 3070

I try to change the GPU and change the riser (all the components) without success.

If you have any idea on how I can use the 4 PCIe slots on the MB, I am stuck :-/

I just command other Riser (another type) but 3 weeks delivery.

On a new riser, everything works well except : the GPU is not recognized and the GPU fan does not even start

 

[Oraklos]

Thanks Nasgul for your feedback.
I try with both Ventus 2x and Ventus 3x from MSI - RTX 3070
I bought them one month and two months ago

One of my friend has the same card and use a riser. So, I bet you explanation is not correct. I just saw that Nvidia intend to create a card "not interesting from mining" for the gamer but hard setting parameters. But I can't imagine Nvidia blocking fully like this.

 

[Oraklos]

Hi there,
I can give the "solution".
The risers I have seem to be really instable. After plenty of different tries, I get the GPU starting on Riser with the PCIe x16 port.

So, no config problem or else... Just bad hardware quality I think.