Question My 1080ti only works in the second slot, but my 1080 works in the first slot

[MoonJo]

Ryzen 7 2700x
MSI x470 gaming pro carbon
2tb Nvme Kingston Fury Renegade
32gb 3600mhz ddr4 ram Corsair Vengeance Pro RGB.
Asus Strix GTX 1080
Asus Strix GTX 1080ti oc
Fractual design 850w PSU

As the title says my new 1080ti doesnt work if used in the first pcie slot, but somehow works in the second one.

The weird thing is that I used my 1080 for years in the first slot with no issues, so how come the 1080ti doesnt work in there.

 

[Lutfij]

Asus Strix GTX 1080
Asus Strix GTX 1080ti oc
Are both GPU's in the system at the same time?

What BIOS version are you on for your motherboard?
For the sake of relevance, Fractal have a number of PSU's in their portfolio, which one do you have, i.e, the model for the unit?

 

[MoonJo]

No the gpus arent in at the same time
I thought It had to do with pcie lanes and how the motherboard manages them so I took out one of my nvme ssds so im not on a 2tb nvme gen 4 (I hope this that it being gen 4 is the problem)

I cant figure out how to upload images on here, as I can find this is the current version of bios:

BIOS Version/Date American Megatrends Inc. 2.E0, 2020-06-10
BIOS Mode UEFI
BaseBoard Manufacturer Micro-Star International Co., Ltd.
BaseBoard Product X470 GAMING PRO CARBON (MS-7B78)

Regarding the psu im not sure If this is the correct one but its the Ion gold 850w