This behavior is observable in Elden Ring and Dark Souls 3. Both games run smoothly in Windowed and Borderless Mode by default. But as soon I use some applications that add overlay on top of the screen (for example: https://github.com/tremwil/SteamP2PInfo and I even tried to write my own external C application that just said: "TEST" in the middle of the screen) both mentioned games begin to have some sort of weird lag that looks like everything updates slowly. For example if I run next to some vertical objects (pillars) I can see how they a bit "fluctuate" and this cause game feels insanely jerky and not smooth. So I went ahead and forced vsync off in Nvidia Control Panel and tried to play the game normally. Even without Vsync both Elden Ring and Dark Souls 3 are running smoothly with no lags and tearing. But when I run external overlay (either P2pInfo I mentioned above or my own C application) my screen begin to have horrible tearing. I don't know why does it happen but it looks like external overlays breaks something related with how Windows interact with vsync / windowed applications which cause all these issues. It's clearly not overlay program issue. The only common things about these overlay program that they are work only with windowed / borderless mode and draw overlay on top of the game window (not internally like MSI Afterburner for example). So is there any settings or anything I can change to prevent this from happening?