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Ask Slashdot: Low-Latency PS2/USB Gaming Keyboards?
An anonymous reader writes "I've a cheap but low latency mouse (A4Tech) and I noticed my trusty old wired Logitech PS/2 keyboard seems at least 50ms slower (if not more) than the mouse when I test with those reaction time sites. I even increased finger travel distance over my mouse button to make it fairer and the difference still remains. So either the tests are slower with keyboards or my keyboard is high latency. Assuming the latter any suggestions for a good reasonably priced gaming keyboard? Extra function keys might be nice but since my hands aren't big what would be better is being able to output a custom key/combo if you hold down (special?) keys while pressing another key. For example I could configure it so if I hold down "Special Key 1" with pinkie or thumb and press 4 it actually outputs 9, and if I hold down shift as well it outputs shift+9 (and not just 9). Being able to replace the capslock key function and have it behave as another key (or a special modifier) would be a bonus — I've never needed capslock and have probably used it more by mistake than for its normal function, or to test how badly a PC has hung."
There is not a single modern keyboard that has 50ms latency. You (humans) have that sort of latency.
As far as response times, all you need to do is increase the poll time on the USB stack, you should be able to set it to ~1-5ms, most keyboards are in the 5-10ms range. You can also get a custom keyboard which is used for psychophysics, they run about $300 and have a guaranteed sub-ms latency. But there must be some firmwares out there that can achieve the same for cheaper. I've tested Arduino Leonardo to about 1-2ms latency (also for psychophysics experiments).
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So this is how far Slashdot has sunk. Keyboard latency? Fuck the submitter and the mod who approved it.
Good-bye
Surely 50 ms is just human response time. I highly doubt a "low-latency keyboard" (even if such a thing exists) could improve your gaming performance...
... to make this an important consideration?
I am very skeptical of the marketing claims of low-latency human input devices like gaming mice and keyboards. I understand the usefulness of special device configuration (e.g., macro buttons), but does a mouse really need to be polled every 1ms (like Razer mice)? In driving tests, the reaction time of a prepared driver is on the order of 750 to 1000ms (http://www.tandfonline.com/doi/abs/10.1207/STHF0203_1#.UeGmimR4a04 --- sorry for the paywall). Obviously, driving is not gaming, but let's suppose a gaming reaction time is half this: 375ms to 500ms. Let's compare two mice: one polls at 1ms and the other polls at 10ms. With a base reaction time of 375ms, the resulting difference is about 3% at worst, 2% at best. Is low-latency input devices where we should be optimizing a player's performance? Does it really matter all that much? Wouldn't it be better to focus on things such as network latency and possibly even OS schedulers?
I admit, I am not a serious gamer and I don't invest heavily in gaming equipment. I would be very interested in hearing objective opinion from a gamer. Does an input latency 10ms really matter? If so, do you have objective data that can rule out the placebo effect?
Mechanical-to-electronic interface is just one. The one you think it's to blame.
Then you have the system interface (the USB and the PS/2).
Then you have the full OS stack with its drivers, event listeners etc.
Then you have the browser technologies (like Javascript stuff) which could react differently to different input classes.
And finally the network latency.
All of them at the same time.
Maybe you are right in blaming the device, but I wouldn't bet a penny on it.
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point
click
drool on keyboard
When using the mouse you just click. This is a very fast, almost reflex like movement of your finger. Your finger is moving millimeters of total distance, and the click is registered as soon as it presses down. A keyboard requires your finger to press down further, and the motion to do that is less of a reflex and more a controlled motion.
In short- deal with it, its a difference in how human reflexes work.
I still have more fans than freaks. WTF is wrong with you people?
I find some old DOS games (emulated) unplayable because some key combinations won't register at all. For example, pressing one arrow key might not work, if another arrow key is already down. This seems to depend on both the keyboard and the motherboard though...
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USB has latency because it is poll based. PS/2 in interrupt based and therefore doesn't have latency.
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I don't know what genre of game the submitter plays, but for fighting games, which I play, input latency can mean the difference between winning and losing. 50ms is 3 frames of lag, which means you need to react 3 frames faster to an overhead or throw. This wouldn't be a problem if everyone used the same equipment, ie PlayStation controller, but if someone had a controller that somehow had lower latency than the regular controllers then everyone who wants to compete would flock to it.
As has been said more than once already, the latency overall lies within you. Perhaps you should try over clocking your brain:
http://www.foc.us/
I plan on getting one, and I don't even game -- disclaimer: you can actually build a crude 2 milliamp transcranial stimulator for about ten bucks, but this looks really cool and contains features outside of my ability to design and build circuits.
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For certain kinds of games, where reaction time is pretty much the be all, end all (like Call of Duty) it does seem like it can make a difference. It isn't that your human reaction time isn't still the biggest thing, but that you make it faster relative to other people and thus gain an advantage. I was, and still am to a degree, skeptical that it matter much but I've tried it and seen results.
So in my case, it was my monitor. I have long used professional screens, at the time it was a NEC 2690WUXi. Nice pro quality IPS screen, fully calibrated for a great image. It runs at 60fps, meaning 16.7ms between images and has about 33.3ms (2 frames) of delay for its image processing time. So basically 50ms from the time the computer sends the data to it, to the beginning of image formation. A few more ms for the image to fully form.
I decided I wanted to see what the 120Hz hype was about, so I bought myself a second monitor, a BenQ XL2420T. It's a cheap TN panel, but very, very fast and has a mode to cut through all processing and lower latency. In 120fps mode you get a frame every 8.3ms, and delay of about 3.4ms until the image start forming, just another 1.5ms until it is complete. So 11.7ms from data to beginning of image formation.
Well I found out two things. One is that you definitely CAN see the difference between 60 and 120 fps. It is actually more noticeable on the desktop, where you have sharp lines and high contrast, but in games too. It is a level of smoothness and fluidity you hadn't seen before.
The other thing is that my performance in Black Ops 2 was quite measurably better playing on the faster monitor. My KDR (kill death ratio, how many times on average you kill another player per time you die) increased by over 0.5, which is a lot. It was just much easier for me to get shots off on people before they could get me.
Now is that all latency? Probably not, the smoother frame rate probably helps too, but it is a difference that is really there. It isn't a case of "Oh you just want you new monitor to be better," or something I have both kinds of monitors and the pro one is what I use 99.9% of the time and for almost all games (I now have a PA301W) because the better colour and image quality is just so worth it. But there is no question for speed sensitive games, the faster display helps me do better.
So how does this apply to mouse and keyboard? I've no idea. I haven't tested it. The keyboard I use is based off of ergonomics, not speed (a Kinesis Freestyle 2, they rock). However perhaps such a thing could help too.
I mean the theory would go like this: Presume you have two people, both with an equal reaction time. Say 500ms if you like. Their computers process and prepare everything for display at the same time. However one guy has a fast screen, and the other a slow screen, like 10ms vs 50ms. Then also one guy has a fast input device, the other guy a slow one, say 1ms vs 10ms. What this means is that the net reaction time, as in the time from the computer saying "This has happened," to the time it receives a response, is 511ms in one case, and 560ms in the other. If you are talking games where a lot of damage is done per shot, that could be enough to make a difference.
I'm not sure that it is worth worry about as much as people do, but I can see how it can make a difference in theory and I was amazed that the fast monitor made as much difference for me as it did. In general though, my recommendation is just stick to games that aren't so twitch based, and use a nicer display.
Forget about latency. It's not that big an issue with decent keyboards.
Just get yourself a decent mechanical keyboard with the Cherry MX Brown switches. The Cherry Blue are good for typists, but not for gamers. The Browns are just right for keyboard gaming. Coolermaster makes about the least expensive one that is well-made. About $80 at newegg. Mine is a Ducky, but it was too expensive. The Coolermaster is every bit as good, and $60 cheaper.
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A mouse button has a hair trigger while you have to push a keyboard key down a pretty good bit before it registers a press. On the reaction time test, the margin between keyboard and mouse narrows to about 10-20ms when I try to make sure that I press down on the key as quickly as possible.
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Hi There,
Your problem sounds very familiar. In FreeBSD's moused there is an "-F" option to make non-gamers mice into gamers mice. Some mice don't like this. Possibly the same trick would work for USB keyboards, that by overriding the USB controllers polling rate in software, you will get the key-presses faster. Look for bInterval field as output from lsusb -vvv (Linux) or usbconfig dump_curr_config_desc (FreeBSD) :-)
Mouse is 50 ms better at the same test than keyboard. This means either the keyboard or the operating system's keyboard processing is at fault.
I have a 60 fps camcorder. If key travel took 3 frames to press a key, I'd be able to test that. Besides, I also own an Apple keyboard (from the "mighty" era), and Apple keys have hardly any travel.
You're obviously not a twitch gamer. Sometimes it's about being 1 ms faster than the other guy. Obviously there are other factors that come into play (like your connection latency) but it all adds up.
then you lost already if it's about 1ms.. connection latency goes up and down by that anyways, but that doesn't necessarily matter, depends on how the game handles it's network compensation logic.
some people keep using any lag anywhere as an excuse though and provide an ample market for hifi gaming gear.. doesn't make them better at guessing where the pointer should be at and where the other guy is moving. the guys who go this route never seem to make it to top end though. they just keep fiddling forever.
as long as you don't have a shitty wireless setup you're as good as golden. some wireless setups have horrible latencies but they become apparent without special testing.
however, using a reaction site written in javascript for testing the difference is stupid though fwiw my chrome and wireless setup gives me about the same for mouse and keyboard. smack middle of average reaction time stats for people as measured with dedicated equipment, so I don't think there's too much of lag going on with my setup. however I would wager that some browsers do keyboard events to javascript at different speed than mouse events..
world was created 5 seconds before this post as it is.
What the system does with the key labeled "Caps Lock" is controlled by the OS, just like all the other keys. Remapping Caps Lock is usually quite easy in any modern system; KDE's Keyboard settings page has options to make it an extra Control or more exotic things like Hyper or Super, and on Windows you can use RemapKey or AutoHotkey.
I still keep at least one PS/2 device, either keyboard or mouse, on every computer. Why? Because no BIOS I have ever seen has the capability to wake up a PC from USB events. Presumably this is due to USB controllers not using hardware interrupts (IRQs), instead relying on polling to give some software-emulated interrupts.
It's so much more convenient to be able to hit the space bar or jiggle the mouse to switch the computer on rather than fumbling beneath the desk for a flimsy power button.
"Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife
I'm only mildly surprised that I didn't see even a single semi-helpful comment yet. Everyone else appears to be bitching about the question, and saying that USB isn't capable of that. It is, of course, with a few caveats. But assuming you're not connecting a HID device to a USB3 port under Linux and expecting it to get better than 125Hz (driver limitation, works fine on Windows), it all works out of the box assuming you have the right connected devices.
A4Tech makes pretty high quality low latency mice, and apparently you have one, but they also have a similar line of keyboards. 1ms response time on both keyboard and mouse, 8-key rollover on keyboard with programmable macro buttons. Try the A4Tech G800V. It's fairly often on sale somewhere.
My only gripe with it is that it has a 'large' enter key and \ is in a funny place. It's well engineered, and not completely over the top like some other 'gaming keyboards' that offer break-off numpad and other weirdness. It's pretty similar to a standard keyboard, merely with the addition of some macro buttons.
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I'm not sure if this is truthful, but it's what I've read in the past. I recall long ago that I was researching this exact topic and came to the conclusion that a good keyboard (Ducky, Filco, Das, WASD, etc) plugged into a PS/2 port is the best solution to combat latency. The reasoning was something like - USB acts by polling the device, so you're pretty much stuck with whatever frequency limitations your driver/port/OS provide. But with PS/2, your input is not polled; rather, it calls an interrupt the second data is available. A little-known bonus is that a lot of the cheesy "gaming" keyboards these days (even some of the mechanical ones!) don't allow n-key rollover unless they're plugged in via PS/2 either. But again, I don't really know the truthfulness of this (aside from the n-key rollover thing, which I experienced with keyboards made by non-dedicated keyboard manufacturers). Any insights, comrades?
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Roccat Isku Gaming Keyboard
http://www.roccat.org/Products/Gaming-Keyboards/ROCCAT-Isku/
I've had one of these for about 6 months now. It's proving to be durable and overall for the money, a great keyboard. Not mechanical though, but its about half the price of a comparable mechanical.
Does recycle the capslock into a kind of new shift key and macro system, so it fits your needs there. For the price, don't think you'll find better. Enjoy!
I know it's rare to RTFS/A on Slashdot, but not doing so makes you miss the point.
This thread never was about human latency, it was about equipment latency. Most humans quite easily detect 3-5ms of latency between their fingers performing an action and something happening, and trained musicians down to around 1ms between hitting a note and hearing it. Equipment should allow humans to perform on their top form, not limit them.
Unfortunately some computer keyboards poll in the 1ms range for no good reason, as the technology could trivially provide response times one or two orders faster without any hardware cost at all.
And that's what this thread is about, not human latency.
That means get a scope or perhaps a Bus Pirate, put it on a key and also on the USB/PS2 data line. Press the key and check the time difference between the two. It may be the keyboard firmware uses a stupid long debounce time for the key press in the event the key takes a while to settle. I guess you'd have to do a similar test for the mouse to make any direct latency comparisons. Overkill, but it'd be the most definitive test.
If you have access to a Teensy, you can make a quick and dirty keyboard with one button and test the latency that way. Hook it directly to an interrupt pin, and use a minimal debounce before registering a key press. Repeat the tests and see if there's still the 50ms lag. That would point to something higher level.
In terms of keyboard recommendations, I recently bought a Razer BlackWidow and haven't had any complaints. The Cherry MX Blue switches might be a bit clacky for some, but I really benefit from the tactile response they provide.
http://bit.ly/1aM29Hm
Late post but to answer his question, but while this is a "gaming" keyboard, there are keyboards on sale for some scratch that promise low latency (2ms it says).