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Comment by Aurornis | Hacker News Reader

> and noticed that significant lag

Only xwayland showed that result. The difference was only a couple milliseconds. That’s in the range where I start to doubt that people are feeling the latency difference. If it was 10-20ms I could believe it, but not when it’s a couple milliseconds.

The author of this post did a good job of getting all of the other confounding settings out of the way. It’s possible that the people complaining that Wayland was slow were starting from an unoptimized situation and as part of switching to some low latency variant they set all the correct settings.

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I think the author’s use of a 500Hz display covers up or minimizes a lot of issues. It’s really easy to look at this data and say 8ms click to flash is fabulous even though he has an config that does 4ms.

A better way to interpret this data is to normalize by the vsync interval or the swap chain depth. The slowest config is 2 frames slower than the fastest. At 500Hz this is 4ms extra which is likely imperceptible to everyone but elite pro gamers. At 60Hz this is 34ms extra which is pretty noticeable to even casual gamers.

Yeah at 120hz each frame is 8ms. So you're only missing a single frame around 30% of the time.

I certainly want my latency as low as I can get it. But I'm pretty skeptical that anyone is truly feeling the difference of a couple ms.

Try musicians that are used to playing extremely high speed semihemidemisemiquavers.

We notice latency. Neil Peart could almost get sample-precise timing, he was so godlike.

Humans are good at predicting stuff, and they can notice when the expected doesn't happen.

But I wouldn't necessarily say that people can notice it everywhere in every state of mind. The medium, context etc all matter a lot.

This[1] study suggests image framerate does not significantly affect our ability to perform predicted moves accurately in time, above a certain minimum which is lower than 24 Hz.

Moving the mouse and then pressing a button, or pressing one key and then another, are both cases of predictive moves.

So it seems one shouldn't rely on framerate when talking about the limits of sensing input lag, at least in general.

[1]: https://jov.arvojournals.org/article.aspx?articleid=2213289

You might be right, 8 ms of total end to end latency is about 1 frame at 120 hz or half a frame of 60 hz, someone would need to be quite competitive to notice that. And the baseline was 4 ms, so going from half a frame of total e2e latency at 120 hz to 1 frame, not much of a difference. Also in 2026 I'm realizing it might be doubtful that many games would still be only x11, so I'm not sure how common it would be to encounter xwayland in a game today realistically.

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