Under EthOS :
Only support one brand VGA card to use at same time.
Example : 9 Gigabyte AORUS GeForce GTX 1060 6G have to use EthOS.
If AMD card , Enable CSM support option.(Path : BIOS/Boot Menu/CSM Support => Enable)
Easy 5 Steps to Install ethOS USB on TB250-BTC PRO http://www.biostar.com.tw/app/en/event/crypto_mining/page7.htm
Note: We couldn't guarantee that overclock VGA card will be work stable and smoothly.