SUMMARY *** NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols. See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports *** When I set my internal screen to 60Hz, the "Show FPS" desktop effect shows consistent 30FPS, and the image feels laggy. When set to 144Hz, Plasma shows correctly 144FPS. This issue appears only in Wayland; in X11 the rendering is just fine. STEPS TO REPRODUCE 1. Open "Configure display settings..." 2. Set monitor (internal/external) refresh rate to 60Hz. 3. Confirm changes OBSERVED RESULT Desktop effect "Show FPS", external tools and personal observation shows that the rendered screen is in 30FPS and feels laggy. EXPECTED RESULT The monitor will render at the same FPS as the refresh rate set in settings. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 6.0.1 KDE Frameworks Version: 6.0.0 Qt Version: 6.6.2 Kernel Version: 6.7.9-zen1-1-zen (64-bit) Graphics Platform: Wayland Processors: 12 × 13th Gen Intel® Core™ i5-13420H Memory: 15,3 GiB of RAM Graphics Processor: Mesa Intel® Graphics Manufacturer: LENOVO Product Name: 82XV System Version: LOQ 15IRH8 ADDITIONAL INFORMATION
I just tested this with AMD Vega 64 using amdgpu driver and I don't have such issue. Works correctly in all refresh rates: 60 Hz, 72 Hz, 75 Hz, 85 Hz, 96 Hz, 100 Hz, 120 Hz, 144 Hz, 180 Hz. So this looks something specific to your setup/GPU/monitor. Maybe you can try different monitor and see if it makes any difference to rule that out.
I cannot confirm it with different PC, but it can be replicated with multiple monitors; via USB-C or HDMI. For clarification; I believe that the external monitors are using my dedicated Nvidia RTX 4050 (as when I disable it the monitors no longer work).
I experience the same behaviour. Operating System: Arch Linux KDE Plasma Version: 6.0.1 KDE Frameworks Version: 6.0.0 Qt Version: 6.6.2 Kernel Version: 6.7.9-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 4 × Intel® Core™ i5-2500K CPU @ 3.30GHz Memory: 11,7 GiB of RAM Graphics Processor: NVC1 Manufacturer: MSI Product Name: MS-7673 System Version: 1.0
I can confirm this is still an issue on Plasma 6.0.3.
*** This bug has been marked as a duplicate of bug 452219 ***