> DXGI flip presentation model doesn’t add input lag anymore
This is only true in certain situations. For non-fullscreen windows it requires that your GPU driver support a feature called "Multiplane Overlay" which is not supported on Nvidia cards before RTX 20 series (probably not older AMD cards either though I'm not sure). A lot of people have disabled it because they've experienced bugs like flickering or stability issues. And a lot of random features will also disable it without notice, like monitor rotation or 10-bit color.
I've also seen Intel GPUs that will only enable this with a single display. Turn on two displays and no windows will ever enter Independent Flip mode according to PresentMon.
I even have weird (most likely) overlay-related issues on my RTX2070, like trying to scroll in Chrome with a YouTube video playing stutters like hell, and the video even occasionally blacking out, or when moving/sizing the browser window, it takes the video a noticeable amount of time to adjust. It's extremely annoying.
That’s an NVIDIA driver bug recently introduced, it’s super annoying. Videos increase the chance of that flicker appearing if you’re on YouTube in their “ambient light” mode thing, since it just blacks out the whole back canvas when it happens.
Right, but DXGI flip in windowed mode is a relatively recent addition and one that’s a net improvement. (Windowed always had an extra delay added due to composition)
This is only true in certain situations. For non-fullscreen windows it requires that your GPU driver support a feature called "Multiplane Overlay" which is not supported on Nvidia cards before RTX 20 series (probably not older AMD cards either though I'm not sure). A lot of people have disabled it because they've experienced bugs like flickering or stability issues. And a lot of random features will also disable it without notice, like monitor rotation or 10-bit color.