MP 1,1-5,1 AMD card to accompany Nvidia in 5,1

[Hps1]

Hello,

I have a 5,1 running 10.13.6 with 3x 1080ti powered by an extra PSU. I'd like to swap one card for an AMD card. This is hopefully so Cinema4D S22 stops lagging like crazy. The AMD card would be the display card.

Is it possible to mix the two, and if so, what cards are recommended? 8gb VRAM would be ideal.

Thanks

 

[KeesMacPro]

From what I've read in several threads in this forum, mixing Nvidia and AMD GPU's in the cMP will lead to issues.
The how's and why's are unknown to me..