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Keyboard latency

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Re: Keyboard latency

#211

Post by Moru »

Kadin wrote: post #197
lightedman wrote: post #175

Earlier quoted context omitted.

"To my eyes, the delay is obvious at 100 ms, noticeable at 50 ms, barely perceptible at 20 ms, and unnoticeable at 10 ms." That's how it goes with my ears when recording as well. Most "Live feedback" mechanisms for guitar programs (heck even computer-made guitar hardware) have about 50ms of latency, which is quite disconcerting when you're doing something heavily timing-based. 10ms is almost imperceptible to me (soun…

This is why I'll never buy a DAC that doesn't have a headphone monitor output on the front panel! The performance of low-latency audio has gotten worse over time, not better, at least on the Mac. (It was better under OS 9 than anytime since, I think.) Another fun test you can do, if you have an analog mixer, is to run some input signal into the mixer, then to the PC, and then from the PC back out, and monitor both th…

As I understand it, when they talk about 100 ms being the fastest possible thing we can notice, they mean if we can notice a reply from a computer was instantanious or if there was a delay. If we get to compare instantaneous to 10 ms lag in realtime sound, we can very easily hear the difference. But if we type a question to a computer and get a text answer within 100 ms we will persive it as being instantaneous.

http://theixdlibrary.com/pdf/Miller1968.pdf

Re: Keyboard latency

#212

Post by dannyw »

rubatuga wrote: post #165

I've done a simple test with my Macbook Air, using the app "Is It Snappy", as mentioned in the comments. I used the keyboard on my macbook, which is a chiclet style mechanism. The tests were all done in triplicate except for TextEdit, (only twice) TextEdit: ~81 ms from key depression to when LCD pixels begin to shift. For Sublime Text: ~86 ms. Both of these text editors are pretty well matched. However, if you boot i…

This is incredible. Single user mode feels like the screen updates BEFORE pressed the keys, like it is time travelling. I guess I've used to the high latency on newer computers.

Re: Keyboard latency

#213

Post by [deleted] »

Nition wrote: post #11
korethr wrote: post #2

IMO, a better measure would be from activation of the switch, as opposed to the beginning of key travel. I don't start waiting for the character to appear on my screen from the moment I begin to press down. My anticipation begins when I feel the tactile feedback of the switch activating (or the switch bottoming out on switches that don't offer tactile feedback). On a keyboard with good tactile feedback, I might not m…

I wouldn't be surprised if the Apple keyboard is the fastest just because it has very shallow keys.

[deleted]

Re: Keyboard latency

#214

Post by digi_owl »

subwayclub wrote: post #210
digi_owl wrote: post #159

Earlier quoted context omitted.

I suspect the culprit is not the hardware, but the software. Back in the day there were very little between the keyboard and the screen, and most of it were either in rom or in ram. Never mind that unless one were dealing with a big iron or similar, multi-tasking was a big nope. These days most OSs have 10s to 100s of processes going right after a first boot on a clean install. And all those can trip something at "ra…

Just the other day I replied to a Reddit thread, and told a gamer who experienced periodic frame drops in CS:GO to check the other system processes. He protested that he had nothing else running, but elsewhere in the thread a Task Manager screenshot revealed that Windows 10 Smartscreen Filter was chewing through files and bottlenecking the HDD(a problem I've also experienced). Basically, desktop Windows has crossed t…

More like desktops in general, and smartphones as well even after the decade long reboot, are running out of actual new stuff to cram in there (in a sense the desktop, bar some security issues, was done with Windows 95).

Thus desktop developers keep adding questionable "quality of life" stuff like file system indexers to justify their continued version releases (never mind avoiding doing actual code maintenance).

Re: Keyboard latency

#215

Post by latigidigital »

ChuckMcM wrote: post #65

I find my typing accuracy is affected by keyboard latency. An interesting way to test this would be to use a sensor to note how the point where a key was definitely "headed down" (say > 10% of its total travel) and then waiting for the message to show up. In older keyboards the main CPU was doing some of the debouncing so it knew "right away" that a keyboard was pressed. That cuts down on latency as well. Another tes…

I'd really like to see more research done on this subject.

I clock about 15 keystrokes per second while typing full speed, and I find serious issues with accuracy using most contemporary keyboards, even on gaming and higher-end OEM equipment.

Edit: Some keyboards are also practically unusable due to dropped inputs above a certain rate.

Re: Keyboard latency

#216

Post by pdq »

sgt wrote: post #26

Has anyone benchmarked the keyboard latency of recent generations MacBook Pro Retinas?

I measured ~62ms for my MBP 2016 in MacOS 10.12.6 using Terminal, with the "Is It Snappy" app.

Re: Keyboard latency

#217

Post by Moru »

ewjordan wrote: post #72
bhj wrote: post #37

Earlier quoted context omitted.

Agreed, and I don't understand the hate many people (seem to) have for them - the most ergonomic keyboards are those that require the least amount of repetitive motion. Not that there isn't an adjustment period, but some seem to pull out their Jump To Conclusion mats a little early.

"the most ergonomic keyboards are those that require the least amount of repetitive motion" Not sure I can agree with that. I was using one of the Apple keyboards for quite a long time while running liveops on an online game (which meant rapid response whenever incidents happened, jumping into shells and constantly typing like my life depended on it), and developed fairly severe wrist problems within a couple months.…

About 18 years ago I started typing on a Microsoft Natural Keyboard Elite. That helped a lot with my wrists. Since then I have upgraded a few times but always the Natural range of keyboards from Microsoft. They are a lot cheaper than the Kinesis Advantage and easier to learn I guess. I would love to try a Kinesis though but don't dare for that price :-)

Re: Keyboard latency

#218

Post by zokier »

mjw1007 wrote: post #7
korethr wrote: post #2

IMO, a better measure would be from activation of the switch, as opposed to the beginning of key travel. I don't start waiting for the character to appear on my screen from the moment I begin to press down. My anticipation begins when I feel the tactile feedback of the switch activating (or the switch bottoming out on switches that don't offer tactile feedback). On a keyboard with good tactile feedback, I might not m…

I agree. Presumably he measured it the way he did because it's easier to measure, rather than because he thinks it's the more meaningful way. (Though maybe his way is more useful if he's interested in whether a keyboard gives an advantage in gaming, rather than whether it's pleasant to type with.)

Probably the easiest way to measure exactly the processing/scan latency would be to swap a key with a low-latency relay.

Re: Keyboard latency

#219

Post by lb1lf »

BoppreH wrote: post #117
pdkl95 wrote: post #92

Earlier quoted context omitted.

> strike a key less than 100 ms after some visual stimuli, I'm sure I couldn't do it The video game "Super Hexagon"[1] is a surprisingly interesting demonstration of this limitation, and how the mind tries to workaround the problem. The higher difficulties ("hexagonest"[2]) seem impossible at first. In the easier levels you can react , but now the time it takes to see the scree, parse the simple graphics, recognize t…

This is also clear on rhythm games like Stepmania. Here's a random video from a keyboard user: https://youtu.be/TWiMnENdcyY?t=56 At this speed the player is reacting (and hitting with correct timing) about ten notes (arrows) per second. This is possible by memorizing and reacting to group patterns instead of individual notes, but more importantly, reacting unconsciously. A player can play at this level without consci…

Also, morse code.

I can comfortably send morse code at ~25wpm, approx. 125 characters/minute. ('Comfortably' meaning others can comfortably figure out what I am trying to send)

That equals ~375 hand movements/minute, or 6.25/second.

(Granted, I cheat - I use a single lever paddle and a microcontroller to get the timing exactly right.)

I've heard people going twice as fast, though that's very rare.

However, people more skilled than I can use a straight key at up to ~35wpm or so - that's ~9 taps a second, while also getting the timing just right without the aid of a microcontroller. That, in my book, is very impressive.

Re: Keyboard latency

#220

Post by stinos »

colanderman wrote: post #9

I'm surprised the "humans don't notice 100 ms" argument is even made. That's trivially debunkable with a simple blind A/B test at the command line using `sleep 0.1` with and without `sleep` aliased to `true`. To my eyes, the delay is obvious at 100 ms, noticeable at 50 ms, barely perceptible at 20 ms, and unnoticeable at 10 ms. Not to mention that 100 ms is musically a 16th note at 150 bpm. Being off by a 16th note e…

While you're factually correct about the musical stuff, note that the auditory system is not at all the same as the visual system, the latter being slower in processing information (i.e. full time for light entering retina to information being ready to do something with in the brain). Also resulting in reaction times for auditory stimuli being faster than for visual stimuli. So you can't just use one system to debunk a fairly general statement made about something visual related. Even though it's still false, but for other reasons.
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