There must be a system difference. I did a bunch of testing last night on the Metroid Prime (MPT) intro sequence,with and without borderless fullscreen with vsync on and without and could not perceive any difference in performance or smoothness. Of the games I have, this game in this scene is one of the few that doesn't run full speed so I use it a lot for testing.
What I have found lately for my system is that I can run vsync without penalty whereas which didn't use to be the case two years ago. With so much that has changed in Dolphin in that time, me switching to Windows 10 and the updates to the AMD drivers, I have no clue why this is but I'm now happy with vsync and exclusive fullscreen mode. It has helped eliminate some mild micro-stuttering I used to have on scrolling titles like DKCR.
What I have found lately for my system is that I can run vsync without penalty whereas which didn't use to be the case two years ago. With so much that has changed in Dolphin in that time, me switching to Windows 10 and the updates to the AMD drivers, I have no clue why this is but I'm now happy with vsync and exclusive fullscreen mode. It has helped eliminate some mild micro-stuttering I used to have on scrolling titles like DKCR.
Windows 10 Pro x64 | i7-9700K @ 4.6-5.0GHz | MSI Z370 Gaming Plus | MSI RX 5700 8GB Factory-OC | 16 GB DDR4-3000