Created attachment 139041 [details] Output of glxinfo I have a multi-monitor setup, with a 1080p laptop screen and a 1440p monitor. When I set my screens in the settings so that the laptop screen is to the bottom-left of the larger monitor (as is the case physically), the whole session becomes extremely choppy (about 1 FPS or less). Turning off the laptop screen (by closing the lid) often resolves the issue temporarily and everything looks normal even after turning the laptop screen back on. However, any screen resolution changes while both screens are on reintroduce the issue. This problem only seems to occur when there is no screen positioned at the 0,0 co-ordinates in the screen configuration. When I place the laptop screen to the top-left of the larger monitor, everything is fine, as well as when the laptop screen is to the right of the larger monitor. It also only occurs when the Rendering backend is set to OpenGL (any version), and only in X11. Wayland does not seem to be affected. SOFTWARE/OS VERSIONS KDE Plasma Version: 5.21.5 KDE Frameworks Version: 5.82.0 Qt Version: 5.15.2
Do you still have frame rate issues if you run kwin using the following command `env KWIN_X11_FORCE_SOFTWARE_VSYNC=1 kwin_x11 --replace`?
(In reply to Vlad Zahorodnii from comment #1) > Do you still have frame rate issues if you run kwin using the following > command `env KWIN_X11_FORCE_SOFTWARE_VSYNC=1 kwin_x11 --replace`? No, with software vsync it seems to be fine.
This bug was reported against an outdated version of KWin. We have made many changes since the. If the issue persists in newer versions can you reopen the bug report updating the version number.