Solution here (added by moderator): Asus Zenbook Pro Duo 2nd screen display issue - #18 by steelx
steelx original post follows:
Thanks for getting back.
I have Windows 10 + Zorin OS 15.3 installed on 1 SSD.
Attaching screenshot of BIOS, I could not find anything related to term discrete graphics
The one option which I found under Advanced -> Graphics Configuration -> "64M" just a input field (but did not had any toggles or term "discrete graphics")