Bootcamp and Vega ii duo, plus another GPU won’t work

[Guest rondocap]

Any time that I have a Vega ii duo installed, I can never get a second GPU to work, such as a regular Vega ii or a W 6800 X duo in Boot Camp

 

Screen flickers on and off and is very glitchy. Works in Mac OS

 

Any idea why this is the case and what I can do about it? tried to reinstall drivers multiple times

 

Source: MacRumors