Disabling MacBook Pro internal display degrades perfomance, introduces flicker

[cloudyafternoon]

I have a new MacBook Pro 13 inch with touch bar, which only has USB-C interfaces. I have one external monitor attached with a USB-C to DisplayPort-Adaptor.

When I disable the internal display and use only the the external monitor, the performance of the desktop UI degrades. Window dragging is not smooth any more, windows flicker while drawing. Menus open with noticable delay.

I have MacOs Sierra 10.12.4 (16E195)

[simon-lang]

Experiencing this exact same issue, however adaptor for me is USB-C to HDMI.

[vegadj]

same issue here,
with macbook air 11" 2015 + apple cinema display 22"

[Eun]

Probably due to the fact that the graphics card is not fully disabled.