High-speed camera measurements find X11 and native Wayland input latency roughly equal

Sources: write-up, HN 48909424
Summary: A 2026-07 write-up by Marco Nett measured mouse-to-photon latency on Linux using a high-speed camera against a 500 Hz display across X11, native Wayland on KDE Plasma, Wayland with variable refresh rate, and XWayland. X11 and native Wayland both landed near 4 milliseconds, VRR was slightly lower, and XWayland added roughly 3 to 4 milliseconds. The author isolated graphics drivers, kernel settings, and compositor behavior across the runs.
Comments: Commenters stress that latency is a property of a specific compositor rather than the Wayland protocol, that a few milliseconds is minor at 500 Hz but closer to a frame at 60 Hz, and that the XWayland penalty likely reflects NVIDIA driver behavior rather than the protocol.
Why it matters: It puts numbers on a long-running X11-versus-Wayland latency argument and shows the compositor and driver, not the protocol label, drive the differences.