The new "Default" is Fullscreen Optimizations ON globally with no way to disable it except on a per game basis. I read previously somewhere that while there is nothing overlayed on the game, it will behave as though it's fullscreen (with the benefits of fullscreen), then when an overlay is pulled up (such as when you use the Windows Key + G) it will start behaving as though it's in windowed mode. My concern is that you'll only get the "performance boost"/resource focus on the target app while no overlays are being used then as soon as you as you add an overlay you'd lose the benefits of fullscreen mode/it would act as though it were in windowed mode. Would this occur with the RTSS FPS overlay? What about the MSI Afterburner overlay? Or, since RTSS maybe intercepts the frame itself in the rendering process is this a non-issue? Thanks, EDIT: Source -- https://devblogs.microsoft.com/directx/demystifying-full-screen-optimizations/ > "To get back this performance overhead, we enhanced the DWM to recognize when a game is running in a borderless full screen window with no other applications on the screen. In this circumstance, the DWM gives control of the display and almost all the CPU/GPU power to the game. Which in turn allows equivalent performance to running a game in FSE. Fullscreen Optimizations is essentially FSE with the flexibility to go back to DWM composition in a simple manner. This gives us the best of both worlds with performance and other features that require the DWM, such as overlays. When an overlay such as the Game Bar is present, the DWM reassumes control of the display, and a slight performance overhead is incurred so that the overlay can be composited on top of the game in a safe and stable way."