How much of your reaction time is your equipment?

Refresh rate is arithmetic

A display only changes at fixed moments. When something happens between two of those moments, it waits. On average you wait half a frame, and that is straightforward division rather than a measurement anyone needs to take.

The framing worth internalising: best-case lag is identical at 60 Hz and 144 Hz. What a higher refresh rate buys you is a smaller worst case and less variation, not a constant subtraction. That is also why the jump from 144 Hz to 240 Hz is only 2.8 milliseconds of frame time.

Televisions are the big one

Panel processing is where the genuinely large numbers live, and it is almost entirely a settings problem. A television in its default picture mode runs noise reduction and motion interpolation, both of which need to buffer frames before displaying them. Measurements of the same set in default mode and in game mode routinely differ by 80 milliseconds or more.

If you are taking a reaction test on a television, game mode is worth more than any other change you could make — more than the mouse, more than the browser, more than practice.

Mouse polling, and where it stops mattering

A mouse reports its state at a fixed interval, and a click landing between reports waits for the next one. At 125 Hz that is up to 8 milliseconds; at 1000 Hz it is up to 1.

Going from 125 Hz to 1000 Hz removes up to 7 milliseconds of worst-case delay, which is larger than the entire gain from 60 Hz to 144 Hz. Going from 1000 Hz to 8000 Hz removes at most another 0.875 milliseconds, which is below the noise floor of everything else in the chain and costs eight times as many interrupts to your CPU.

Claims about wireless mice being within a fraction of a millisecond of wired are usually traceable to vendor marketing rather than to a lab. If you want a real comparison, review outlets measure click latency with a protocol analyser over hundreds of clicks and publish per-model figures. Use those.

Does a faster monitor make you better?

There is one peer-reviewed study, with 101 gamers tested at 60, 144 and 360 Hz. Moving up from 60 Hz produced significant improvements in target accuracy and target destruction time, and moving back down degraded them.

The result that gets left out of the marketing: performance did not significantly differ between 144 Hz and 360 Hz. The authors conclude that gains diminish at higher refresh rates, which puts 144 Hz somewhere near the practical optimum. Worth noting that the study includes authors from a graphics hardware company, and it still reports the null.

You will separately find a claim that players at 180 frames per second have kill-death ratios 90 percent better than players at 60. That figure is published by a hardware vendor with no sample size or methodology, and the vendor itself adds that correlation is not causation. People with fast machines also have better hardware generally, play more, and care more.

What we do about it

We measure your display’s refresh rate by timing forty animation frames and reporting half a frame as the uncertainty it adds. That figure sits next to your score, because a number without its error bar is half a number.

It is a floor rather than a total: panel processing and peripherals add more that a web page cannot see. If you want your fastest honest score, use a wired mouse on a monitor in game mode, and take the reading as a measurement of you plus your equipment either way.