dual GPU possible on Asus ROG Strix z-790 e wifi II?

[Hyena-D28]

Hi..

I just build my PC using MB ASUS ROG Strix z790 E wifi II. my plan the spec is:

MB ASUS ROG Strix Z-790E Wifi II

intel i7 14th gen

64GB Corsair Vegance Memory

2x GPU Asus RTX 2080 Ti.

when finished, I found problem whereas only 1 GPU is detected, I attached 1 GPU on PCIEX16 Gen 5 slot and other on PCIEX16 Gen 4 slot. I cannot attached both GPUs on PCIEX16 gen 4 slot because too thick. as Information, Strix Z-790 E wifi II has 3 PCIEX 16 slots, 1 gen 5 and others gen 4.

if I use monitor output from GPU on gen 5 slot, other GPU is not working. and vise versa.

any solution for this? I need 2 GPUs because I want to play flight simulator with multi monitor.

sorry for my english.. 

[JohnAb]

The 2080TI has 3x DP and one HDMI. Will that not work for you? I'm actually not sure if both cards will work at once but I think I've read that some people have done it.