I noticed today that when I tumble the Scene View in the Unity editor, its stuttery. Never had this issue before and my MacBook Pro has a Vega 20 so it's pretty well-equipped. I tried opening an empty scene and the scene view is still stuttery. Tried a few different versions of Unity, same problem. Somehow not an issue in play mode: the same scene which would be stuttery while tumbling the camera is now smooth while play mode is on. I suspect this could have something to do with the macOS 10.14.4 update I installed yesterday, but who knows.