Is this a number that came from an actual benchmark or from some marketing material from a keyboard maker? I ask this because [1] finds latency (measured from touching the key to the usb packet arriving) of 15ms with the fastest keyboard and around 50ms with others, though apparently some manufacturers have since improved. Or are you talking about midi keyboards where I guess latency is more noticeable to users?

[1] https://danluu.com/keyboard-latency/

From the countless review and small time YouTube channels that test these things regularly.

I think that post must be a few years out of date - and moreover by its own admission doesn’t even test hardly any “gaming” keyboards. There is a tremendous amount of competition in keyboards that has been building for the past 10 years.

Input latency is now a marketing thing like horsepower, and there are reasonably reputable [1] places and countless small time YouTube reviewers that test these things. It’s not like it is difficult to improve latency, and now that it is something that is competitively marketed it is delivered on.

[1] https://www.rtings.com/keyboard/tests/latency

Personally I think it’s a bit ridiculous. This fetishization with minimizing latency to now sub-ms levels doesn’t necessarily lead to better performance as many top level gamers do not use the lowest latency level keyboards. But that doesn’t change the fact that modern mainstream gaming keyboards can hit a latency far below 50ms.

The link I posted was 2017. The site you link gives quite different ratings. I assume partly it is different methodology (the site you link tries to account for key travel somehow and they do something with a display and try to account for display latency rather than using a logic analyzer), but I’m not really sure. For some keyboards in common:

- apple magic keyboard (? vs 2017) 15ms vs 27ms

- das keyboard (3 vs S professional/4 Professional) 25 vs 11/10ms

- razer ornata (chroma vs chroma/chroma 2) 35 vs 11.4/10.1ms

Interestingly it is not some simple uniform difference: the Apple keyboard does much worse in the rtings test, perhaps getting not much of a bonus from key travel compensation. But the das keyboard vs the razer that are 10ms apart on my link perform equally on rtings (but maybe I found the wrong model). I don’t have a good explanation for that discrepancy.

I know it is 2017, but that is a very long time in the gaming/mech keyboard market. I remember just about 10 years ago when mech keyboards were a niche for weirdos and a few others that swore by their Model M's - you now can buy these in Walmart. The point about discrepancy is well taken* but I think the bigger point is on the rtings list the number of offerings that are an order of magnitude lower latency - such that the methodology used in your link is not even viable.

Why is using a high speed camera and a logic analyzer less viable than measuring the end to end latency and trying to subtract the computer part of it? Or are you suggesting that a solenoid should be used to press the key instead of a finger?

The latter. Even the linked article points out the inherent limitations.

I was thinking more of the time a human finger needs to push the button down.

That's because a lot of input hardware uses moronic debouncing.