OpenGL - Fullscreen Exclusive under-utilizes the GPU

[JosJuice]

(10-06-2021, 12:14 AM)Franpa Wrote: Is it really just a difference in how Vsync handles FPS below the refresh rate for OpenGL? Reducing by a flat 3rd as though Triple Buffering was in effect while Windowed mode doesn't do that?

If you have a 120 Hz monitor, then yes (120 divided by 3). But if you have a 60 Hz monitor, you should be getting either a flat 60 Hz or a flat 30 Hz with vsync.