[magicalhippo]

While reaction response is around 100ms, for predictive movements, ie press a button exactly when a bouncing ball hits the ground, average people can get down into 5-7ms of timing accuracy[1]. Trained people can get below 4ms in certain cases.

Of course, the brain adapts. I played an online shooter at >100 FPS using my 144 Hz monitor (when that was the best). I visited a buddy who's PC could only muster 30-40 FPS, and he asked me to show me how I played, since he struggled.

I sucked so bad due to the extra input lag. Felt like my character was running in a pool of molasses. But after about 15-20 minutes my body adapted, and my performance started increasing and my hits started connecting more reliably. I got to about 90% of my regular performance after 30 or so minutes.

So while one could tell back to back, one could also compensate. But at some point the extra input lag will matter, and will get you killed or make you miss that shot. Hence why I could only get up to ~90% of my normal performance on my buddy's PC.

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

[lII1lIlI11ll]

Well, of course people can generally see the difference between 30 and 100+ FPS but it is much bigger delay than 1ms OP claimed they can distinguish.

[magicalhippo]

As noted in the paper I linked to, display framerate did not affect the timing precision of their participants, from 120Hz down to 24Hz. So it's more about feeling it rather than seeing it.

If you can be accurate to below 5ms, an additional millisecond of input lag makes a big difference.

[lII1lIlI11ll]

That paper measures our margin of error when syncing to a perfectly predictable rhythm, not our ability to detect system latency. Applying that to an FPS doesn't really work for two reasons. First, enemies are erratic, meaning you are mostly relying on your reactive visual-motor pipeline, which is bottlenecked by ~150ms anyway. Second, even for purely predictive shots, your brain subconsciously calibrates out fixed hardware lag.

I'll concede that pure prediction absolutely exists in FPS games-like tracking a falling player with the LG in Quake 3 or landing a predictive mid-air rocket. In such cases smoothness of high FPS helps, but adding a 1ms drawing delay to those 500FPS (what the article is about) won't be noticeable at all because your brain naturally calibrates out constant hardware delay.

[magicalhippo]

It only calibrates it out over time, that was what my 100+ FPS to 30 FPS story was about.

So yes I agree over time you wouldn't be able to tell 1 ms from 2 ms, but a skilled player doing back to back comparisons might be very different.

[lII1lIlI11ll]

Well, I don't think this is the case and I haven't seen any research to convince me otherwise.