The stutter may occur if the game is not in the real full-screen mode. It seems sometimes the in-game full screen setting doesn't work as expected.

How to enable the real full-screen mode?

Go to C://Users/your-username/Save Games/Arkane Studios/Dishonored2/base/dishonored2Config

Edit this file by adding this line

r_fullscreen "1"

Save the file, restart game.