I have messaged Asus about this i get nothing in reply.
Someone must have bios modded by now! So we can use what ever gpu we want.
like 8 random Nvidia rest Amd instead of the restriction of using 8x p106-90 /104-100 first, in order to fill the rest upto 19 slots with Amd cards.
Bitsbetrippin used 8x p106 first and managed to get up to 21 with a PCI-E expander. So the bios is adaptable to a degree.
There has to be micro code somewhere to lift the p106 restriction.