Note that the results will differ between compositors, different GPUs, and different configurations. This is somewhat less the case with X11 since there is only

Note that the results will differ between compositors, different GPUs, and different configurations. This is somewhat less the case with X11 since there is only one X server implementation (that Linux desktop systems use, anyhow.) I think there may still be the issue that many compositor/GPU combinations don't get hardware cursor planes, which would definitely cause a latency discrepancy like this.