Some quick findings regarding NULL and G-Sync in The Outer Worlds (a DX11 game).
With NULL set to Ultra, but without a frame cap (framerate set to "Unlimited" in-game and no cap in RTSS), the FPS is capped at 1 frame below the display's maximum refresh rate, and gameplay is mostly a smooth experience (flat line in RTSS's frametime graph).
Much, much better than using the game's own framerate limiter, and even slightly better than setting RTSS to -3, related to the refresh rate. That's my limited experience with NULL set to Ultra, so far (it was globally set to "On", before).
jorimt wrote:The majority of games in Windows 10 (be they DX9, 11, or 12) now default to the OS's hybrid borderless/exclusive fullscreen mode, unless you disable fullscreen optimizations per exe (though, I think DX12 will use it either way; haven't tested that myself).
This allows quicker alt+tabs and the appearance of secondary overlays (volume bar, game bar, etc) by, as far as I understand it, allowing the DWM to engage temporarily for those elements, while still retaining exclusive fullscreen functionality when the game window is focused by disengaging DWM composition again.
As for Window's HDR configuration, from what I know, that's a mess regardless of AMD, Nvidia, or the game in question, and is primarily on Microsoft to address (if they ever will; that, along with multi-monitor configurations using mixed-refresh rate monitors).
Forgot to mention that I disable fullscreen optimizations for all possible games - the only exceptions being those downloaded from the Microsoft Store, due to the nature of UWP. Even the new ones, that are supposed to be Win32, still have locked executables hiding in encrypted folders. I'd love to find out a way of disabling fullscreen optimizations even for those, but have yet to succeed.
For DX12 titles, the "fake" exclusive fullscreen mode behavior is the same, aside from MW, which works in a slightly different way. Still, the HDR limitation is related to the fact that the game still isn't truly running in exclusive fullscreen mode, as the games that do can have HDR enabled regardless of the desktop settings.
HDR used to be much worse, but 1903 mostly fixed the biggest issues. Before that, not only the implementation was flawed (incorrect colors and levels), but enabling HDR would also mess up audio (Atmos, in particular). Playing RE2 in both HDR and with Atmos was an exercise in patience like no other.