geekhack
geekhack Community => Keyboards => Topic started by: dmbr on Tue, 03 April 2012, 12:47:28
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I have a couple straight-forward questions that I've so far been able to turn up a solid answer for:
Would increasing the USB polling rate on my keyboard reduce input lag?
Could this damage my keyboard?
Thanks!
PS
Hello, longtime lurker first-time poster :)
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Zero benefit.
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Thanks for the reply.
What about risks to the hardware? If it's relatively safe, I'd like to give it a shot...
From my understanding, a higher polling rate would allow the reports from the keyboard to be picked up faster by the computer.
Would you mind elaborating why this wouldn't reduce input lag, please?
I did find this (see post with testing and analysis a few down): http://geekhack.org/showwiki.php?title=Keyboard+scan+rates&viewfull=1&page=8&do=comments#post409032
As you can see the polling rate of the USB protocol has a big influence on the scatter of the delays. If the polling rate of USB would be set to 1ms all the results would probably tightened (?) by 7ms.
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How fast do you type ?
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I'm more concerned with each individual keystroke registering as an action onscreen with as little latency as possible (gamer here).
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Just my 2c but i don't think you would be able to press the keys fast enough for it to make any difference.
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Let's assume it would reduce input lag by a few mS. There's still tens of mS lag introduced by the controller (scanning, debouncing etc). So you haven't gained much! One problem is that the keyboard firmware doesn't expect to be able to send that many reports, so it probably wouldn't be able to make much use of them.
On the other hand, I can't see any harm in forcing a faster report rate.
Carry on reading that thread starting from Namelos's post - there is some good info there (amongst the obvious trolling by some).
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Just my 2c but i don't think you would be able to press the keys fast enough for it to make any difference.
How fast I type isn't really relevant to my interest; basically, I want to hit the "a" key and have my character move left in-game as soon as possible from when "a" is pressed.
Let's assume it would reduce input lag by a few mS. There's still tens of mS lag introduced by the controller (scanning, debouncing etc). So you haven't gained much! One problem is that the keyboard firmware doesn't expect to be able to send that many reports, so it probably wouldn't be able to make much use of them.
On the other hand, I can't see any harm in forcing a faster report rate.
Carry on reading that thread starting from Namelos's post - there is some good info there (amongst the obvious trolling by some).
Hey, good riddance to every millisecond of input lag reduced! If there's no risk of damaging my hardware, I'm going for it :)
Thanks for the replies!
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How fast I type isn't really relevant to my interest; basically, I want to hit the "a" key and have my character move left in-game as soon as possible from when "a" is pressed.
Hey, good riddance to every millisecond of input lag reduced! If there's no risk of damaging my hardware, I'm going for it :)
Thanks for the replies!
If you can type 1000 characters per second which is exactly 60 times faster than Sean Wrona,, then you are in absolute dire need of 1000hz polling rate.
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Not sure what the disconnect is here, I'm talking about input lag for a single keystroke registering. I'm not sure why typing speed keeps coming up?
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You are not overclocking anything here, only changing the rate at which USB controller asks keyboard for new data.
Obviously polling *does* introduce extra lag, precisely every stroke gets a random delay between 0 and the inverse of polling rate (e.g. 10ms for 100Hz, 1ms for 1000Hz). However, as Soarer said, keyboards have much bigger and more random lags anyway. And there are random delays everywhere else - between USB and CPU, in software and so on.
What tp4tissue said about typing speed is technically true, but of course it has no importance for this topic.
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I know this is a really old topic, but I somewhat interested. Mostly in how you can even tell what the polling rate of your keyboard is. I have a leopold tenkeyless with browns which I recently bought, and I would like to know those technical specs. How does one even go about messing with a keyboard's polling rate?
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I know this is a really old topic, but I somewhat interested. Mostly in how you can even tell what the polling rate of your keyboard is. I have a leopold tenkeyless with browns which I recently bought, and I would like to know those technical specs. How does one even go about messing with a keyboard's polling rate?
Its probably an epic new feature in Razr's latest driver software.
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I know this is a really old topic, but I somewhat interested. Mostly in how you can even tell what the polling rate of your keyboard is. I have a leopold tenkeyless with browns which I recently bought, and I would like to know those technical specs. How does one even go about messing with a keyboard's polling rate?
It really doesn't matter. Debouncing is somewhere 8+ ms; every USB keyboard polls faster than 125 Hz. Or if you're super worried use a PS/2 keyboard which is interrupt-based.
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bro you don't need to overclock your polling rate for gaming that is just ridiculous. sc players with 200+ APM don't have any issue and I highly doubt you are getting anywhere near that. It is seriously just a waste of time. If you are feeling latency issues while your gaming, it is probably the monitor.
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Does it have more GIGS? ? ? ? ? ? ?
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This issue is still slightly relevant, if you play rhythm games.. Out side of that, no other software "depend on impeccable keyboardin'
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I would think that a bunch of "geeks" would just try to answer the question. Regardless of whether or not being able to overclock your keyboard is important, is it possible? Isn't that the kind of stuff geeks want to know? And I also didn't specifically ask to be able to do so. What I really wanted to know was whether there was a way to see what your keyboard's technical specs are that aren't officially listed, like polling rate.
Is this a question people don't know the answer to so they just say that it doesn't matter?
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I would think that a bunch of "geeks" would just try to answer the question. Regardless of whether or not being able to overclock your keyboard is important, is it possible? Isn't that the kind of stuff geeks want to know? And I also didn't specifically ask to be able to do so. What I really wanted to know was whether there was a way to see what your keyboard's technical specs are that aren't officially listed, like polling rate.
Is this a question people don't know the answer to so they just say that it doesn't matter?
We don't know the answer because it isn't worth our time to figure it out and test it. Just cause we're "geeks" doesn't mean we want to know every fact about everything technology related.
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What we really need to do is find a way to run a parallel interface between the key matrix to the PC to eliminate all lag. Like on the old terminal keyboards.
Connect that to a PCI Express 3.0 x16 slot directly connected to the system bus (not through a PCI extension chip), and you'd juke left as fast as your CPU could process it. An SLI bridge might enable you to send the keypress straight to the rendering chips.
- samwisekoi
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I would think that a bunch of "geeks" would just try to answer the question. Regardless of whether or not being able to overclock your keyboard is important, is it possible? Isn't that the kind of stuff geeks want to know? And I also didn't specifically ask to be able to do so. What I really wanted to know was whether there was a way to see what your keyboard's technical specs are that aren't officially listed, like polling rate.
Is this a question people don't know the answer to so they just say that it doesn't matter?
We don't know the answer because it isn't worth our time to figure it out and test it. Just cause we're "geeks" doesn't mean we want to know every fact about everything technology related.
I didn't really say you would know every fact. But I didn't think you would dismiss someone's curiosity so bluntly either.
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I would think that a bunch of "geeks" would just try to answer the question. Regardless of whether or not being able to overclock your keyboard is important, is it possible? Isn't that the kind of stuff geeks want to know? And I also didn't specifically ask to be able to do so. What I really wanted to know was whether there was a way to see what your keyboard's technical specs are that aren't officially listed, like polling rate.
Is this a question people don't know the answer to so they just say that it doesn't matter?
We don't know the answer because it isn't worth our time to figure it out and test it. Just cause we're "geeks" doesn't mean we want to know every fact about everything technology related.
I didn't really say you would know every fact. But I thought you wouldn't dismiss someone's curiosity so bluntly either.
LOL, he's jus trollin' you bro...
I personally wouldn't dismiss overclocking keyboards. In fact, I would love an excuse to buy heatsinks to mount to the damn thing...
I think it's possible to increase polling rate on the Computer end, but on the Keyboard end, there's nothing to overclock if there's only a hardware interrupt setup, as nothing is being calculated..
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I would think that a bunch of "geeks" would just try to answer the question. Regardless of whether or not being able to overclock your keyboard is important, is it possible? Isn't that the kind of stuff geeks want to know? And I also didn't specifically ask to be able to do so. What I really wanted to know was whether there was a way to see what your keyboard's technical specs are that aren't officially listed, like polling rate.
Is this a question people don't know the answer to so they just say that it doesn't matter?
We don't know the answer because it isn't worth our time to figure it out and test it. Just cause we're "geeks" doesn't mean we want to know every fact about everything technology related.
I didn't really say you would know every fact. But I thought you wouldn't dismiss someone's curiosity so bluntly either.
LOL, he's jus trollin' you bro...
I personally wouldn't dismiss overclocking keyboards. In fact, I would love an excuse to buy heatsinks to mount to the damn thing...
I think it's possible to increase polling rate on the Computer end, but on the Keyboard end, there's nothing to overclock if there's only a hardware interrupt setup, as nothing is being calculated..
overclocking your keyboard is more delusional than preferring topre to any other rubber dome
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These topics ARE troll magnets.
Namelos measured latencies for some keyboards, which sparked a good discussion. The link above in dmbr's post is dead, but the wayback machine does have that page. If anyone works out how to get page 9 and on from it, speak up!
Short version... all the latencies add together. Reduce any of them and it's a win. Namenlos' results showed that controllers varied a lot, but even the fastest could be improved on.
By polling rate, do you mean scanning the keys, or the USB polling rate?
USB polling is in most cases 125Hz, otherwise the advertising usually makes a point of it being faster (even then, some lie). Tools such as USBlyzer can query it. Low speed USB + any interval -> 125Hz, lol. High speed USB is the only way to get faster polling without hacking the OS.
Scanning rates are probably typically a bit higher now than they used to be, but still mostly around 200 to 500 Hz, at a guess. There's no easy way to measure it. Unless you have a scope or frequency counter - then it's easy! The only way to increase it would be to replace the controller. Faster scanning rates are good for two reasons - reduced latency, and reduced debounce time (indirectly, by being a better measure of time).
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Again, my primary aim was to see if there is a way to check specs like polling rates that are not officially listed? A piece of software that does this perhaps? I'm not even asking about overclocking. I just want to be able to look at these specs.
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Thank God for you Soarer. A real actual answer. I want to cry.