Anyone have any suggestions to this problem, I am all ears.

I have one of my rigs which uses a Asus Prim z270-a when I put the 6th GPU in it will not POST to the bios screen therefore not start up.

From troubleshooting it only happens if I have 2 GPUs plugged into the X16 slots, if I only have one it works fine.

I have changed the BIOS to the recommend from the thread here for the z270-a and set it all to GEN2.

Any other suggestions?