About the fans being 100% all the time, it was happening to me too on my temporary case.
These "open" GPU's are blowing hot air in every direction. Make sure your cards are not blowing hot air in the direction of the motherboard, because that hot air will bounce back and heat up the neighbor GPU's, which in turn will heat their neighbors even more.
Thank you for the settings. I will post my results as well.
I have one gpu on the mobo and 5 on the risers. My rig case is 7 gpu capable on the shelf.
I will distribute gpus as much as I can to improve air flow.
As another measure I will put Asus into a position where it breathes the freshest air from the front.
Right now it is it in between other gpus.
But as far as I see MSI has better temps and cooling overall.
Also when one finds a sweetspot for undervolt mV value, is applying this mV value to all GPU speedssets other than the first set (300 Mhz-750 mV) best practice?