FFS

read the damn manual, it clearly states no more than 8 standalone AMD cards are supported


this means you can have up to EIGHT AMD GPUs on this mobo
but go ahead and complain if your 8+ amd setup is not working

i never build rigs above 6 Vegas (i only use vega64, + FE) and they run boringly stable at 44MH/s Ethash, 1980H/s Cryptonight

for details on how to achieve this visit my thread
https://bitcointalk.org/index.php?topic=2549085.msg25986603#msg25986603