HN Gopher Feed (2017-10-16) - page 1 of 10 ___________________________________________________________________
Keyboard latency
248 points by darwhy
https://danluu.com/keyboard-latency/___________________________________________________________________
Stenzel - 1 hours ago
Compare with musical keyboards where not only key number but also
the velocity matters, so each key has two electrical contacts, and
the whole thing is usually scanned around 10kHz for proper velocity
measurement. Although key contacts are arranged in a diode matrix,
the latency is usually below 2 ms, even with good old MIDI.So
neither the keyboard matrix nor the debouncing justify a latency of
10 ms or above.It is nice to see that latency is an issue in gaming
now, similar to realtime audio, where most operating systems are
still not very usable - with the exception of OS X.
xigency - 1 hours ago
Now to learn to type with a keyboard... or game I suppose.
lanius - 1 hours ago
Now that would be fun! I think it would be possible to achieve
a reasonable typing speed given the right "keyboard layout"
(aka the QWERTY equivalent for musical keyboards).
wwarner - 58 minutes ago
I've been wondering about this for longer than I care to admit. I
always felt the perceived responsiveness of my old sparc 20 was
much better than pcs I used 15 years later, and I thought it had to
do with keyboard latency and interrupt processing.
colanderman - 2 hours ago
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 even at that speed is ? especially for
percussive instruments ? obvious.On the other hand, if you told me
to strike a key less than 100 ms after some visual stimuli, I'm
sure I couldn't do it ? that's what "reaction time" is.
xbkingx - 6 minutes ago
The more obvious example is to watch a video encoded at 10 frames
per second followed by a 30 fps video. Does it look different? If
yes, something's wrong with the statementThere are plenty of
examples on YouTube if anyone's interested.
AmVess - 2 hours ago
Yes, and something like a touch interface is very obvious,
too.Look at this video on Youtube from Microsoft Applied Sciences
Group: High Performance
Touch.https://www.youtube.com/watch?v=vOvQCPLkPt4You can plainly
see that 100ms is an eternity. While keyboards aren't the same
thing, but high latency is noticeable. I had to change a keyboard
because of the near eternity of when I pressed a key and when it
registered on the screen. The difference between the old and the
new is quite stark.
gregmac - 1 hours ago
Hm, neat. I notice about the same result -- 0.1 is quite
obvious.If you want to blind A/B test yourself, run this:
DELAY='0.1'; VALUES=(0 0); VALUES[$((RANDOM % 2))]=$DELAY; alias
test_a="sleep ${VALUES[0]}"; alias test_b="sleep ${VALUES[1]}"
Adjust DELAY as you want, and then use test_a and test_b and see
if you can guess which is which, then run alias to see for sure.
tomxor - 11 minutes ago
neat, 100ms is blatantly obvious, I can't imagine anyone not
discerning that one.I can get down to 24ms but no less... the
weird thing is that 24ms is still completely obvious to me
(clearly shorter but obvious in comparison to no delay), with a
single test I can see which variable has the delay every time,
but 1ms less and I can't... which makes me suspect it's being
quantised due to any of the various things in between sleep and
the output, display, driver, X, terminal emulator, CPU etc.With
that it's actually possible that my 24ms is larger than 24ms
and is also being quantised to a larger duration (but not
larger than 100 for sure).It would be interesting to be able to
test with some dedicated hardware.
spott - 1 minutes ago
25ms is 1.5 * (1/60)... Is your monitor running at 60Hz?
Risord - 1 hours ago
Btw your display can be the next bottle neck on 10ms scale if
typical 60hz was used.
azernik - 1 hours ago
Another point is that, even if a bit of latency isn't noticeable
(say, 20 ms), when added to other sources of latency it can make
things noticeably worse.EDIT: Which the original author said
better than me:> Another problem with this line of reasoning is
that the full pipeline from keypress to screen update is quite
long and if you say that it?s always fine to add 10ms here and
10ms there, you end up with a much larger amount of bloat through
the entire pipeline, which is how we got where we are today,
where can buy a system with the CPU that gives you the fastest
single-threaded performance money can buy and get 6x the latency
of a machine from the 70s.
stebalien - 32 minutes ago
This rule comes from UX design user studies. However, the actual
rule is that people perceive an event happening within 100ms as
"instantaneous". Or, in other words, two events happening within
100ms of each other won't feel like distinct events. This doesn't
mean that users won't notice the delay and it doesn't even mean
users won't be frustrated by it, it's just a matter of human
perception of distinct events in time.Unfortunately,
programmers/UX designers have a tendency to generalize this rule
and use it to excuse slow user interfaces.
olegkikin - 54 minutes ago
Measuring using sound should be more precise. Even a bad mic has
orders of magnitude more time resolution than a 240fps
camera.Something like click-to-beep.
ChuckMcM - 53 minutes ago
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 test case might be to put a USB -> PS/2
adapter on the keyboard. This lets the onboard CPU know to send the
keycode as soon as it has decoded and debounced it.
petepete - 1 hours ago
I can't see the merit in that particular test. It's the actuation
point that matters.For more depth than anyone really needs, see the
r/mechanicalkeyboards
wikihttps://www.reddit.com/r/MechanicalKeyboards/wiki/switch_gui...
microcolonel - 4 minutes ago
I've been experimenting with alternative protocols to HID. I'm not
satisfied with fixed-interval input polling out of sync with vsync;
it takes way too many samples to reach the desired latency (and
especially jitter!) numbers.As for keyboards, there's no real
excuse not to just have a Bigass? shift register (or a couple) and
address every keyswitch with a trace and an interrupt crossbar.
There's a limit to how cheap a good-enough keyboard can ultimately
be, so a difference of a few cents in BOM and assembly, and
slightly more intricate membrane layouts is not worth crying over.
_wmd - 45 minutes ago
I'm no a hardware guy so this may be a stupid question, but while
watching the Microsoft Research video and pondering the energy
required to scan the fine wire mesh on the touchscreen quickly
enough to reach that latency, I started wondering why keyboards and
touchscreens scan row+columnwise at all..Would it be possible to
arrange the mesh in a kind of accumulator, where the top level
output for each axis is wired to diodes connected to groups of
lines (that in turn can be directly sampled) are connected to their
own set of descendent lines until enough groups exist to connect to
individual rows and columns.. something like:
ROW RR1---------RR2----------+----------RR3------------RR4
| | | | +_+/\+_+
+_+/\+_+ +_+/\+_+ +_+/\+_+ r0 r1 r2 r3 r4
r5 r6 r7 r8 r9 ra rb rc rd re rf So controller
sleeps waiting for interrupt from ROW, tests which output from
RR1..RR4 is set, then only scans the 4 rows within that group.
Computer keyboards aren't perfectly square but maybe a lookup table
could translate a perfectly square wiring configuration into a
logical key (well, I guess the microcontroller is already doing
this)
alasdair_ - 1 hours ago
Isn't a big part of the reason "gaming" keyboards cost so much
because they can register more than three keys (sometimes four)
being hit at the same time - something many cheaper keyboards
cannot do due to the way they are wired?
DeRock - 1 hours ago
This is known as key rollover, see:
https://en.wikipedia.org/wiki/Rollover_(key)It is a result of the
matrix wiring of the keys, though more expensive keyboards will
have them wired individually, mitigating this issue.
munchbunny - 26 minutes ago
Yes, n-key rollover sometimes comes up. In practice, I've only
had it become an issue in the wild either when more than one
player is sharing the keyboard or, in some rare games, primarily
simulators, where you might need to hold multiple keys.
korethr - 2 hours ago
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 move the switch through it's full travel --
just a little bit above and below the activation and reset points.
Nition - 2 hours ago
I wouldn't be surprised if the Apple keyboard is the fastest just
because it has very shallow keys.
robotresearcher - 20 minutes ago
Quoth the fine article:> Contrast this to the Apple keyboard
measured, where the key travel is so short that it can?t be
captured with a 240 fps camera, indicating that the key travel
time is < 4ms.
Heliosmaster - 2 hours ago
They mentioned it being a likely culprit in the article :)
Nition - 2 hours ago
Oops, yeah I just got to that part. My fault for not reading
past the conclusion before posting.Still, I guess in a way,
timing it from the start of a key press is the most real
measure of actual latency when you want to press a key. It's
just got nothing to do with the processor etc.
zitterbewegung - 1 hours ago
This is anecdotal so YMMV. I have a Macbook Pro 2017 and the
shallow key travel makes me feel like its more accurate than
the one on my previous Macbook Pro 2015 with longer key travel.
Also, I feel like I am typing faster.
marssaxman - 1 hours ago
Sounds like a good argument for the superiority of shallow
keys. I've always liked Apple keyboards - actually used their
wired USB keyboard for a long time specifically because it felt
like typing on a Powerbook.
codemonkeymike - 1 hours ago
Superior is a strong word, if your preference is to bottom
out flat keys then thats all well and good. I personally type
like I am playing an instrument, pressing just enough to
activate and then letting the key push my finger up. I find
no enjoyment on typing on an apple keyboard, which I am now
and it also causes me joint pain from all the constant
bottoming out.
andyfleming - 1 hours ago
That's fine though. It's about the experience end-to-end. I
love the apple keyboards. I still type faster on them than
other keyboards, including high-end mechanical keyboards. The
short keys and actuation feel responsive, yet I've never felt
like I've accidentally triggered a key.
baxuz - 59 minutes ago
I'm currently using a mechanical 60% keyboard with the
following layout: http://www.keyboard-layout-
editor.com/#/gists/c7f9f0ac904b21...Truth be told, I also
prefer scissor switch keyboards, but there aren't any on the
market that support the features I'd like: - configurable
keys & layers on a hardware level - 60% layout - NKROApple's
magic keyboard would be great if it supported
configuration/NKRO and didn't cost so outrageously much.
hueving - 37 minutes ago
Custom build at wasd keyboards work? I love that place.
cjbprime - 1 hours ago
Same -- I like doing speed typing on typeracer, and after
going through mech keyboards and different switch types for a
few years, I'm consistently fastest on a non-mechanical
ThinkPad USB chiclet keyboard.
confounded - 1 hours ago
I've recently got rid of several extremely expensive
mechanical keyboards to go back to a new ThinkPad chiclet.
I am somewhat embarrassed to say it's been fantastic.
bhj - 1 hours ago
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.
deathanatos - 54 minutes ago
There's essentially no range of motion in a MBP keyboard
anymore: there is no difference between not pressing the
key, actuating the key, and bottoming out the key. Some
people (such as yourself) seem to prefer it, but to me it
feels much rougher than comparable keyboards, like typing
on a hard plastic surface. There is no give or play in the
keystroke. Compared to a Lenovo T460p's keyboard (the other
machine I own), the Lenovo is a lot "softer" to type on.
(And quieter, too.) Mostly, I dislike the feel.Now, my
wrists also hurt. Now, when I'm not travelling, I was using
an external Apple keyboard, not the MBP's primarily, so I'm
hesitant to blame the MBP's keyboard directly. The external
Apple keyboard has a greater keystroke distance from start
to bottoming out, but still has like zero distance between
actuation and bottoming out. (For some keystrokes,
particularly ^+Tab and ^+Shift+Tab, I find it hard to keep
control actuated, despite it being fully depressed; it just
seems to require a lot of pressure to keep things in
electrical contact). The pain in my wrists didn't start
until I started using Apple keyboards, and has mostly
stopped since I've replaced them. (I now primarily use an
ErgoDox EZ, primarily for the split/ability to
independently position my hands. I had tried, and had
similar success w/ a Kinesis Freestyle, but I didn't own
it.)(I used a MBP keyboard for ~4yrs, with an ergo keyboard
of some kind for when I'm not travelling for ~half of that.
I've used Thinkpad's of varying models for ~10 years. Now,
I could just be getting old, but replacing the Apple
keyboard is what made the difference thus far for me. It
doesn't make a lot of sense to me, admittedly: my wrists
are, I feel, in the same bad position on the Lenovo as they
are on the MBP/Apple keyboard.)
bitwize - 6 minutes ago
If you can't adjust to an Apple keyboard (and don't have
RSI), the problem is you -- not the keyboard. Retrain
yourself to type softly.
ewjordan - 23 minutes ago
"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. To the point where I almost had to leave the
job on disability, per my doctor's orders.On the
recommendation of a friend, before taking that step I tried
switching to a Kinesis Advantage for the better wrist
alignment and less "hard" keystroke bottom as compared to
the chiclets on the Apple keyboard. It was a bit of a
learning curve (~2 weeks to get up to full typing speed
when using it every day, a couple more to push past it),
but at the end of it my wrists got better almost instantly,
and I never had problems again. My typing speed went up as
well.I'm not sure how much of that improvement is due to
the better alignment of keys (there's almost no hand
movement when typing, and your wrists are always neutral)
and how much is due to the bigger key action and softer
bottom, to be fair.Edit: it's worth mentioning that I'm
also a boxer and a piano player, so my wrists take a lot of
abuse on a regular basis. YMMV and if you're not having
problems, I definitely found the Apple keyboards to be very
easy and fast to use.
krashidov - 1 hours ago
Agreed. When I first used them I hated them, now I can't
really use anything else.
ehsankia - 12 minutes ago
Actual activation might be hard to get, but when the key bottoms
out is probably the best way to go. Or even better, why not post
both when key travel starts and when it ends. If people are
really curious, they can model a linear scale and use the key
response plot to guess exactly where the activation happens.
baxuz - 49 minutes ago
A weird result with the Das 3 keyboard (25ms) considering it uses
a cherry MX switch, same as the Kinesis (55ms).The OLKB and
Ergodox don't state the switches used, but it's almost certainly
a cherry MX style switch with non-modified actuation points
compared to the original.
bastijn - 2 hours ago
Didn?t watch good enough. There are mechanical keyboards in the
review as mentioned below. My bad. Original comment below for
future reference.? - original comment ? -True gaming keyboards
have mechanical switches which activate on first key press, not
on full key down. Bit disappointed no mechanical keyboard was
tested as they are perceived to be the ultimate keyboards when
speed matters.
dom0 - 1 hours ago
> which activate on first key pressNo, mechanical keys have
some travel before actuation as well.
mhweaver - 1 hours ago
I see several mechanical keyboards in the list (das, ergodox,
kinesis advantage, olkb planck, possibly others)
[deleted]
eikenberry - 1 hours ago
Mechanical key switching activate differently based on the
switch. Most with feedback activate on the feedback, ie. when
you hear/feel the click. So it isn't first press or full key
down, but somewhere in the middle.
vith - 1 hours ago
The most common key switch for gaming oriented mechanical
keyboards is probably the Cherry MX Red. Its actuation point is
around 50% of the way through the key travel.Buckling spring
switches, membrane domes, topre (membrane dome + spring), etc.
all have actuation points somewhere in the middle of the key
travel, not at the start or end.
DeepYogurt - 1 hours ago
Further those gaming keyboards have longer than normal key
travel.
mjw1007 - 2 hours ago
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.)
ehsankia - 14 minutes ago
If you want a clear point, then why not use the moment it
bottoms out. So when key travel ends, instead of when key
travel starts. In most cases, it'll be much closer to the
actual activation. If you want to be even more thorough,
publish both times (which you can get from a single video).
LoSboccacc - 1 hours ago
the article specifically states the reasons for why he messured
the whole travel, no guesswork needed> This is because, as a
human, you don?t activate the switch, you press the key. A
measurement that starts from switch activiation time misses
this large component to latency.
mjw1007 - 1 hours ago
That's effectively providing a definition of the latency he's
discussing, not an explanation of why that's the sort of
latency he finds interesting.But I see he does goes on to say
that he cares about game performance, rather than typing
experience: ? If, for example, you?re playing a game and
start dodging when you see something happen, you have pay the
cost of the key movement, which is different for different
keyboards. ?For me, I don't care about the time after switch
activation, rather about time after the tactile feedback (the
"click"). Ideally the character would appear on the screen at
the same time as the click; not after, and not before. If a
keyboard can 'cheat' and activate the switch before that and
hide some latency, that's fine by me.
dom0 - 1 hours ago
Seasoned gamers preload keys they are anticipating to use.
On my keyboard I have less than a millimeter of travel from
the preloaded point I use (which is right in front of the
tactile bump and is quickly trained) to actuation.In
tacticale switches the bump and the making of the contact
are mechanically connected.Using the moment of finger/key
contact quite obviously selects for travel, among other
things.
jetpacktuxedo - 16 minutes ago
>In tacticale switches the bump and the making of the
contact are mechanically connected.Nope! This is rarely
(if ever?) the case. In alps switches, for example, there
are two totally separate leafs, one of which handles the
tactile feeling and the other of which is responsible for
the actual actuation. If you browse through Haata's
Plotly[1] you can see that many switches actuate well
after the tactile bump. Though they are often pretty
closely related in terms of their depth in the keypress,
they are wholly unrelated from one another
mechanically.[1] https://plot.ly/~haata
sundvor - 1 hours ago
If you game on a mechanical keyboard, you've pretty much
worked out exactly where the switch points are and will be
working the keys in a fashion different to normal typing. So
I'm not quite buying the way the measurements were made vs
the purpose of the tests.
Splines - 23 minutes ago
Do you really press every possible key down almost to the
switch point, and then when you want to actuate the key,
press it a tiny bit further?I would guess (and maybe I'm
wrong about this) that you rest your fingers on the
keycaps, and press them in as far as needed to actuate, but
no further. The key still needs to travel.
matthavener - 2 hours ago
PS/2 keyboards are used by serious gamers because the scan rate is
higher than USB.See https://superuser.com/questions/16893/do-usb-
or-ps-2-keyboar...
theandrewbailey - 2 hours ago
Saying that PS/2 boards are "scanned" is inaccurate, as they
trigger an interrupt immediately on a keypress.
rubatuga - 2 hours ago
Doesn?t the micro controller in the keyboard still scan, and
then send a ps/2 signal?
valarauca1 - 1 hours ago
Most mechanical PS2 keyboards are a diode cascade.You
pressing the key triggers a wave of electricity cross the
keyboard which is converted into the PS2 waveform, and pumped
out at the same rate of the incoming clock waveform.OLD PS2
keyboards don't generally have internal digital micro-
controllers, they're effectively analog, the logic they do
contain is blindly simple. This is why some struggle with
N-Key Rollover.---OFC this is if you are using an -old- PS2
keyboard. I'm still using an 80's IBM Model M and above it
roughly how it works.
kmill - 20 minutes ago
I am having a very difficult time believing this.- I cannot
find about "diode cascades" having anything to do
keyboards. The closest is the usual diode matrix to deal
with simultaneous key presses.- The PS/2 interface involves
sending scan codes, parity bits, and start and stop bits.
How exactly does a "wave of electricity" get converted into
a PS/2 waveform without some digital electronics?- All the
old schematics for mechanical keyboards I could find were
the usual matrix scan. Even a textbook from the
1970s.Anyway, reference please. I'd find it very
interesting to see how such a thing would work.
duskwuff - 7 minutes ago
This is absolutely untrue for any PS/2 keyboard, as well as
for most pre-PS/2 PC keyboards (incuding AT and XT
keyboards). All keyboards have always had a microcontroller
in them which is responsible for scanning the key matrix
and sending output over the serial link. (In PS/2, it's
also responsible for reading input to change the state of
keyboard LEDs.) There is nothing analog about them
whatsoever.Here is a set of pictures of an IBM Model M, for
instance. The microcontroller is clearly visible in the
ceramic DIP40 package.http://www.clickeykeyboards.com/model
-m-gallery/1985-ibm-mod...
HugoDaniel - 2 hours ago
do serious gamers avoid v-sync ? even at 120Hz they get at least
~8ms * 2(double buffer) latency right ?
dsr_ - 2 hours ago
Yes, they want freesync or g-sync monitors with high refresh
rates.
a_t48 - 1 hours ago
Or a good enough machine so that you never dip below native
framerate.
sgarman - 57 minutes ago
Even so you would never use vsync as it will introduce
input lag in most gaming engines.
sgtmas2006 - 21 minutes ago
Most competitive players will have their own configs for
competitive play etc. I have tournament/LAN configs,
online play configs, and my video settings mostly stay
the same. All tuned for lowest latency and highest
visibility.
gsich - 1 hours ago
Isn't PS/2 interrupt based? So there would be no scan rate.
Haven't looked at your link though.
dfox - 29 minutes ago
There are two "scan" rates: the rate at whitch keyboard matrix
is scanned by whatever electronics is inside keyboard (that is
probably independent of the outside interface) and the rate at
which the interface is able to process input events, which for
PS/2 means faster that the keyboard can produce them (as
keyboard is essentially bus master on the AT/PS2 keyboard
"bus") and for USB means as fast as the *HCI pools keyboard for
interrupt events (old Apple's ADB works the same way and is in
fact to some extent inspiration for USB <3.0 and Firewire "one
big bus" high level model).Edit: then there is third approach:
simple keyboard/input devices with serial interfaces, where
host provided clock is used to both clock the interface and
keyboard scan logic. In essence the whole keyboard then looks
like one big shift register. Keyboards that works this way
includes original Macintosh, most Wyse and DEC terminals and
MIT/LMI/Symbolics Lisp machines (and probably pre-sun4 Suns,
sun4 and later have rs232-derived ionterface), also this is the
way how controllers for Nintendo consoles before Wii work (IIRC
Nintendo calls that "EXI bus") and how PlayStation 1/2
controllers work. IMHO this is to some extent where the idea
behind SPI comes from.
yathern - 2 hours ago
For what it's worth, that answer is now 8 years old - I'm curious
if this has changed since then.
revelation - 2 hours ago
I've gotten a FTDI down to 2 ms RTT, so if done right (using
isochronous transfer) you can get USB down to 1 or max 2 ms.
Looking at the latencies quoted here and in the article it's
certainly not the problem.Notice that just getting a thread
scheduled every 2 ms is already impossible for Windows,
certainly one running a game. You'll get a bunch of outliers
within the second. So even if you got your keyboard down to 5
ms, great, but you are not running an operating system that can
reliably do something within that timespan!
eertami - 1 hours ago
>So even if you got your keyboard down to 5 ms, great, but
you are not running an operating system that can reliably do
something within that timespan!Maybe I'm not understanding,
but that doesn't seem correct.Most people (gamers) are
running mice at 500/1000Hz polling rates and you can easily
verify the movement made in each 1-2ms update. (And it is
most definitely a noticeable difference going from a standard
125Hz rate to even 500Hz.)
ssfrr - 1 hours ago
Don't confuse throughout and latency. The mouse may be
measuring and sending data every 1-2ms, but that doesn't
say anything about the latency before the data is handled.
munchbunny - 15 minutes ago
This is also a pretty important point: most monitors
refresh at 60hz anyway even if your game seems to be
measuring much higher framerates, so there's a worst case
floor of ~17s on just visuals lagging behind input
because you're waiting for the next screen refresh
anyway.The mouse measuring data every 1-2ms will increase
the quality of the motion tracking, but it won't
necessarily help you with latency unless the data gets to
the game fast and the game handles the data quickly.This
explanation by John Carmack comes to mind... it's a good
reminder against a lot of the hardware fetishism that is
mixed into otherwise good advice about gaming setups.
https://superuser.com/questions/419070/transatlantic-
ping-fa...
SebiH - 2 hours ago
A more recent video claims that the PS/2 advantages are
negligible even for serious gamers (around 3:40)
https://www.youtube.com/watch?v=AWkvzycD5PE
ghusbands - 1 hours ago
The message therein directly states that latency isn't
noticeable for those keyboards and hence, according to the
article, is simply uninformed.
sp332 - 1 hours ago
The PS/2 protocol is incredibly slow. Just sending two bytes over
the wire via PS/2 takes 1.3 ms.
[deleted]
rbanffy - 2 hours ago
On the debouncing thing, Razer announced one with optical switches
instead of electrical.
enthdegree - 1 hours ago
Yep, also capacitive and Hall-effect switches don't need
debouncing.
gsich - 1 hours ago
Here is a video where someone is testing USB latency, although with
USB hubs:https://www.youtube.com/watch?v=nbu3ySrRNVc
sgt - 1 hours ago
Has anyone benchmarked the keyboard latency of recent generations
MacBook Pro Retinas?
M4v3R - 1 hours ago
I don't have a way to measure raw USB events, but it takes around
90 ms between me pressing a key on the Macbook's (2015 model)
keyboard and a character showing in the TextEdit.app.
skykooler - 13 minutes ago
Some of that is surely in the OS and display however. I wonder
how you'd go about measuring the latency of a laptop keyboard?
lolc - 1 hours ago
By coincidence I just replaced my last Apple Keyboard with an MS
4000 today. I find it curious that they are both at the top of the
list, even though I've never considered hardware latency an issue.
[deleted]