My FPS drop from about 160 to 100 if i open the scoreboard.
Edit: made a video
https://drive.google.com/open?id=1r4z_TEYHlKlXtfL6j02XESajPPGmuYI-
As you can see in that instance my FPS drop from about 150 to 110 as soon as i open the scoreboard. Pretty sure it depends on the amount of players on the scoreboard.