# Which is better for keyboards: USB or PS/2?



## EastCoasthandle (Jul 9, 2011)

I haven't seen much about this but I wonder if current USB keyboards has anything over PS/2 type keyboards?
From things like:
-keystroke delay
-ghosting
-durability
-etc


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## francis511 (Jul 9, 2011)

Usb is better. I still buy ps2 keyboards to work with an old kvm switch , but that`s the only reason to go that way.


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## cheesy999 (Jul 9, 2011)

PS/2 keyboards have some cool features though, they can turn your PC on when its compleatly off, (where USB's just do it from standby/hibernate)

they also don't take up a USB port 

I use PS/2 keyboards for compatibly with Old bios' and OS installs (also because i have no need to buy a new one)


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## Drone (Jul 9, 2011)

I use ps/2. I see no reason to use usb if I have a ps/2 port


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## kciaccio (Jul 9, 2011)

Drone said:


> I use ps/2. I see no reason to use usb if I have a ps/2 port



Me too.


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## hat (Jul 9, 2011)

Steelseries says:



> We absolutely recommend using the PS/2 connector when possible. First,it will give you total freedom with no limit to the amount of simultaneous key presses. And, equally as important, using the PS/2 may just improve your overall gaming experience. The reason is that when you use a USB keyboard your computer is actually using CPU time polling your keyboard. The higher the polling rate the more CPU time is used to perform the polling. And because of the built-in debounce rate found on any quality keyboard, any polling rate above 200Hz is simply a waste of CPU time and really just a result of pointless marketing hype. Unlike USB keyboards a PS/2 keyboard isn’t polled at all. The keyboard simply sends a signal to the computer as key presses are made, which causes a hardware interrupt, forcing the CPU to register the signal.



I did have to turn my sensitivity down in some games after switching to a PS/2 keyboard, but that could also just have been a change in my own sensitivity level. It's pretty hard to measure that sort of thing.


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## FordGT90Concept (Jul 9, 2011)

PS/2 always works.  I've never met a PS/2 keyboard/computer (that had a PS/2 jack) that didn't work.  I've had a lot of USB hiccups though--especially related to accessing the BIOS.

I used to use a PS/2 + VGA KVM but have moved to DVI + VGA + USB + Audio KVM.  The KVM is the only reason why I switched to USB.  I still often have to break out the PS/2 keyboards though for ornery computers (e.g. good luck getting USB to work on a Windows 95 computer).


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## hat (Jul 9, 2011)

Yeah, I once ran into an error message from the BIOS telling me that there was an issue with my CPU's bus speed of 200MHz wasn't supported and it would run at a lower frequency of 266MHz at reduced speed (this was after doing a BSEL mod on a Celeron 430). This error appeared before USB initialized, so I couldn't press y to continue. Needed a PS/2 keyboard for that.


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## jpierce55 (Jul 9, 2011)

I doubt they do. FWIW I have a keyboard that is over 8 years old and PS/2. It still works great.


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## MxPhenom 216 (Jul 9, 2011)

PS/2 are awesome, because most PS/2 keyboards are mechanical!


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## EastCoasthandle (Jul 10, 2011)

So PS/2 it is, thanks...


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## Hayder_Master (Jul 10, 2011)

USB is the new shape connector, so if you like it or not PS2 become over soon like FDD.
Don't forget old dead shape connector for mouse and keyboard which was called serial,‎‏ ‏and the other one it was look like PS2 it was work untill last P3 but it's gone when P4 come.


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## twilyth (Jul 10, 2011)

It's been years since I've had a problem with a USB keyboard - even the wireless variety and even over a KVM (which only emulates a basic keyboard - to get full functionality you need a KVM with DDM - dynamic device mapping).

But then I've been changing hardware pretty frequently the past several years given my crunching jones (honestly, it's worse than crank or smack).  I think the bottom line is how often will you use it on hardware that is more than a few years old.  I think that's going to be most people, even if maybe not most people on TPU.  So from that point of view I would have to say PS/2, but ONLY for that reason.


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## specks (Jul 10, 2011)

You really wont notice a difference in performance using the either PS/2 or USB. I Just stick to PS/2 because it was made for keyboards.


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## AppleB (Jul 11, 2011)

Ps2


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## EastCoasthandle (Jul 11, 2011)

For your information...The Das Model S has a 6 key roll over for usb and full key roll over using PS/2.


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## FordGT90Concept (Jul 11, 2011)

By the way, PS/2's advantages (except being hardware interrupt-based) are pretty much lost on computers running (U)EFI.


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## WhiteLotus (Jul 11, 2011)

Wait they still make PS/2 keyboards?


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## EastCoasthandle (Jul 11, 2011)

Yes and no.  Most will come with a usb to ps2 adapter.  An adapter that I don't have fond memories of.  Over time I've noticed that the weight of both pushing on the ps2 port itself (a few years back).  I didn't even noticed anything until it would only plug in on a downsloping angle.  This did take a while before it started happening but none the less I stopped using them.


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## LAN_deRf_HA (Jul 11, 2011)

Was using an asrock board the other day that wouldn't let me into the bios with a ps2.


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## EastCoasthandle (Jul 11, 2011)

I found this thread very interesting.  It discusses response times and how a slow controller might be queuing up the data and sending it out of order.  That may explain where "teh" came from.  
thread

Looks like this question was asked before (usb vs ps2)


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## scaminatrix (Jul 11, 2011)

Another vote for PS/2. So much so, I'm actually quite angry at ASUS for only giving one PS/2 ports on some of it's mobo's. I use a PS/2 mouse aswell, and I was not happy at having to find a USB mouse or a converter just to use my rig.


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## Goodman (Jul 11, 2011)

WhiteLotus said:


> Wait they still make PS/2 keyboards?



Exactly! my thought...

It's been years since i see a PS2 Keyboard or mouse in stores around here (3+years) all you could buy was/is a USB to PS2 adapter...

I frankly don't care about PS2 port , they never hold quite right , always got loose after a while or get your feet to barely touch the wire than it moved a little & Keyboard doesn't work anymore & push it back in doesn't help you have to restart you PC in order for the PS2 to work again..

So yeah! USB is much better IMO


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## FordGT90Concept (Jul 11, 2011)

EastCoasthandle said:


> I found this thread very interesting.  It discusses response times and how a slow controller might be queuing up the data and sending it out of order.  That may explain where "teh" came from.
> thread


"Teh" is just a very common typo that has been happening since teh (haha, that was unintentional but I left it there just to demonstrate) invention of the QWERTY keyboard.  I think it happens because the left hand does some 70% of typing so it is trained to respond quicker than the right hand.  As such, it is faster to hit e than h so your brain thinks it hit h but, in fact, it already pressed e.  I doubt it has anything to do with 5-pin DIN, PS/2, nor USB.


There's really no advantage for using PS/2 on mice.  Most mice these days are USB with a PS/2 adapter and mice are useless in BIOS so, yeah, it's mostly keyboards where PS/2 is still relevant.


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## cheesy999 (Jul 11, 2011)

Goodman said:


> It's been years since i see a PS2 Keyboard or mouse in stores around here (3 years) all you could buy was/is a USB to PS2 adapter...
> 
> I frankly don't care about PS2 port , they never hold quite right , always got loose after a while or get your feet to barely touch the wire than it move a little & Keyboard doesn't work anymore & push it back in doesn't help you have to restart you PC in order for the PS2 to work again..



you must have a dodgy socket, i've never had problems with a loose connector?


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## scaminatrix (Jul 11, 2011)

FordGT90Concept said:


> There's really no advantage for using PS/2 on mice.  Most mice these days are USB with a PS/2 adapter and mice are useless in BIOS so, yeah, it's mostly keyboards where PS/2 is still relevant.



My local electronics shop does an optical PS/2 mouse that has 5 buttons and only costs £7!! Nice mouse too, really good feel and durable, even with my abuse. I've always stuck with this mouse, and I'll probably buy another if this one dies. Don't really know why I prefer PS/2 mice  Might be because of all the problems I had with XP using a USB KB and USB mouse (couldn't install one without the other lol) 



cheesy999 said:


> you must have a dodgy socket, i've never had problems with a loose connector?



Same here, but I've seen some n00b PC's with bent PS/2 pins etc.


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## Goodman (Jul 11, 2011)

EastCoasthandle said:


> I found this thread very interesting.  It discusses response times and how a slow controller might be queuing up the data and sending it out of order.  That may explain where "teh" came from.
> thread
> 
> Looks like this question was asked before (usb vs ps2)



The guy Deckguy adam that posted a PDF on the link you just posted date from 2001 so that was a year before USB 2.0 & we're now at USB 3.0 lol!


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## Sasqui (Jul 11, 2011)

Reading this thread and wondering if there really is any empircal evidence for one vs. the other based on EastCoast's criteria

My opinion:  if you have a PS2 keyboard you really like, go with it... and vise versa.


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## Goodman (Jul 11, 2011)

cheesy999 said:


> you must have a dodgy socket, i've never had problems with a loose connector?



Problems not really but never felt right some how for me & yes knock the wire out with my feet at least once i can remember , but the thing is if your keyboard stop working because of loose connection or what ever reason you have to restart the PC in order for your PS2 to work again , at least USB you just unplug & plug in again & it back at working , got to love plug & play...



scaminatrix said:


> Same here, but I've seen some n00b PC's with bent PS/2 pins etc.



Been using PC since 1989 & i never bent any pins just don't like PS2 & really glad we got USB now


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## scaminatrix (Jul 11, 2011)

Goodman said:


> but the thing is if your keyboard stop working because of loose connection or what ever reason you have to restart the PC in order for your PS2 to work again , at least USB you just unplug & plug in again & it back at working , got to love plug & play...



That's a very good point - I had to reinstall a mate's OS because he plugged the KB in while at the Windows XP login screen. Well, he said that's all he did


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## EastCoasthandle (Jul 11, 2011)

Goodman said:


> The guy Deckguy adam that posted a PDF on the link you just posted date from 2001 so that was a year before USB 2.0 & we're now at USB 3.0 lol!


The year is not relevant to the discussion of "teh" or the slower controller.  So that makes no difference to the discussion.  Unless you think USB was invented last year .
And so far there are no current usb 3.0 only keyboards that I know of.  

For example, what was explained (in part) is that the PS/2 has a first-in-first-out buffer.  While you think when it was posted is antiquated the ps2 is still faster then USB polling rate that's used for usb keyboards.


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## Goodman (Jul 11, 2011)

EastCoasthandle said:


> The year is not relevant to the discussion of "teh" or the slower controller.  So that makes no difference to the discussion.  Unless you think USB was invented last year .
> And so far there are no current usb 3.0 only keyboards that I know of.



You know the way you write that it almost sounds like you're saying that there is only USB 3.0 keyboards...  

Anyhow all i am saying is in speed there is no differences between them (keyboard use) but the connector/Port is much better on USB & it is Plug & play , no need to restart or shutdown the PC to plug in a device unlike the PS2 devices


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## FordGT90Concept (Jul 11, 2011)

Sasqui said:


> Reading this thread and wondering if there really is any empircal evidence for one vs. the other based on EastCoast's criteria


-PS/2 has been around since the 1987 so support is common place and the format itself has long been mature.
-USB has been around since 1994.  Since then, it has had many growing pains with Windows not having good support with it until at least SP1 on XP (2000s).
-PS/2 is natively supported in virtually all ATX AMI and Phoenix BIOS.
-PS/2 works on hardware interrupts.  USB basically mimics these interrupts.
-One advantage USB has over PS/2 is that it is plug n' play capable where plugging in a PS/2 device often requires a computer restart.


Specifically:
-keystroke delay - USB would have the disadvantage because it is more complex.  The difference is not humanly detectable though.
-ghosting - Say what?
-durability - Connection standard is irrelevant on this metric--unless you're specifically talking the durability of the connector.  In which case, the pins on PS/2 can be more easily damage than those on USB but PS/2 is shrouded by a metalic ground which makes it stronger when attacked.  They're also less likely to randomly pop out.


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## LAN_deRf_HA (Jul 11, 2011)

So the best gaming keyboard would be ps2, mechanical, and short keyed? Someone get on that.


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## EastCoasthandle (Jul 11, 2011)

LAN_deRf_HA said:


> So the best gaming keyboard would be ps2, mechanical, and short keyed? Someone get on that.



A PS2 mechanical keyboard shouldn't have any ghosting issues and offer something in the neighborhood of 50 mill vs 20 mill key strokes from traditional rubber/plastic sheet design (or whatever they call them).  And from what I know those keyboards are often using Cherry (blue, black, brown) mechanical key switches.


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## FordGT90Concept (Jul 11, 2011)

EastCoasthandle said:


> ...traditional rubber/plastic sheet design...


Dome switch.  The types are listed here: http://en.wikipedia.org/wiki/Keyboard_technology


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## BumbleBee (Jul 11, 2011)

another problem with USB is it can only do 6+4 rollover which is plenty but keyboards today use a standard matrix so your not even getting that. I think losing plug and play is a small price to pay.


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## EastCoasthandle (Jul 11, 2011)

Hmm, I think Deck still sells PS2 specific keyboards.




BumbleBee said:


> another problem with USB is it can only do 6+4 rollover which is plenty but keyboards today use a standard matrix so your not even getting that. I think losing plug and play is a small price to pay.


I think Steelseries 6GV2, Deck and Das offer 6 key rollover when using usb but if you using the PS2 adapter (6GV2/Das) you get full n-key rollover.


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## BumbleBee (Jul 11, 2011)

EastCoasthandle said:


> Hmm, I think Deck still sells PS2 specific keyboards.



yes and instructions are included how to change the cable to USB or vice versa.


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## EastCoasthandle (Jul 11, 2011)

BumbleBee said:


> yes and instructions are included how to change the cable to USB or vice versa.



Funny that their price is lower then on Performance PC


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## theJesus (Jul 11, 2011)

FordGT90Concept said:


> In which case, the pins on PS/2 can be more easily damage than those on USB but PS/2 is shrouded by a metalic ground which makes it stronger when *attacked*.  They're also less likely to randomly pop out.


I'm not sure about you, but I'm not too worry about my connectors being attacked.


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## BumbleBee (Jul 11, 2011)

EastCoasthandle said:


> I think Steelseries 6GV2, Deck and Das offer 6 key rollover when using usb but if you using the PS2 adapter you get full n-key rollover.



yes. you can probably count on one hand how many mechanical and rubber dome keyboards even output 10 characters over USB. Deck is incompatible with USB to PS/2 adapters.



EastCoasthandle said:


> Funny that their price is lower then on Performance PC



it's always been like that.


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## EastCoasthandle (Jul 11, 2011)

BumbleBee said:


> Deck is incompatible with USB to PS/2 adapters.



That portion of my post has already been ninja'd.


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## scaminatrix (Jul 11, 2011)

FWIW, "Trust" still make PS/2 Keyboards, they're sold at Asda's


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## EastCoasthandle (Jul 11, 2011)

scaminatrix said:


> FWIW, "Trust" still make PS/2 Keyboards, they're sold at Asda's



No surprise that there are some PS2 keyboard makers out there.


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## scaminatrix (Jul 11, 2011)

EastCoasthandle said:


> No surprise that there are some PS2 keyboard makers out there.



Seems there was some confusion on whether they were still made or not, my post was mainly for them


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## BumbleBee (Jul 11, 2011)

the keyboard also needs diodes to achieve full n-key rollover. not all keyboards with a PS/2 connection have them.


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## EastCoasthandle (Jul 11, 2011)

ABS
Adesso
Cherry
Das
Deck
Ducky (are they still in business?)
Filco
(IBM Model M if you can find it)
Razer
Rosewill
Steel Series 7G/6Gv2


This is just a short list of where you can find some mechanical keyboards.  But those with PS2 will vary.

Edit: 
I found a list here


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## kid41212003 (Jul 11, 2011)

Aren't they fading out the PS/2 port? Many of new mobos don't have it anymore.


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## EastCoasthandle (Jul 11, 2011)

kid41212003 said:


> Aren't they fading out the PS/2 port? Many of new mobos don't have it anymore.



They are offering a single ps2 port for either keyboard or mouse.  

---
Found some more information:



> Polling Rates and Response Times
> While it is very useful for mice, it's just about meaningless for keyboards. Let's assume for a minute that all switches have the 5ms debouncing time of Cherry MX switches (which is being very generous). Even if you had super human speed and reflexes, every single key would be delayed by at least that much. So really, any polling rate over 200Hz (at best) is absolutely useless, and nothing but market hype. It may even be a bit detrimental, because you'd be wasting CPU time polling the keyboard unneededly. And unlike USB keyboards, PS/2 boards aren't polled at all. They simply send the signal to the PC whenever they are ready to, which causes a hardware interrupt, forcing the CPU to register that keystroke.
> 
> PS/2 or USB?
> PS/2 wins on three fronts: First, it supports full n-key rollover. Second, PS/2 keyboards aren't polled, but are completely interrupt based. And third, it is impossible for it to be delayed by the USB bus being used by other devices. There are two types of USB transfer modes - the interrupt transfer mode (USB polls keyboard, when key is sensed the USB controller sends the interrupt to the CPU), and the isochronous transfer mode, which reserves a certain amount of bandwidth for the keyboard with a guaranteed latency on the bus. Unfortunately, there are absolutely no keyboards made that use the latter, because special controllers would have to be used, thus making it cost prohibitive.


post

Wow, he even has info on the black, blue, brown Red, and clear Cherry switches.  
post


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## BumbleBee (Jul 11, 2011)

EastCoasthandle said:


> ABS
> Adesso
> Cherry
> Das
> ...



you can order Ducky from China. ABS M1 was discontinued a year ago and the Microsoft Natural Ergonomic Keyboard 4000 with Cherry MX Brown was a mod.

you can order Leopold from elitekeyboards.com


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## EastCoasthandle (Jul 11, 2011)

gotcha


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## FordGT90Concept (Jul 11, 2011)

theJesus said:


> I'm not sure about you, but I'm not too worry about my connectors being attacked.


It's a ware out there--until ZIF takes over.


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## LAN_deRf_HA (Jul 11, 2011)

Has anyone seen a slim key mechanical keyboard? I've seen the slim keys for sale individually but never on a product.


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## BumbleBee (Jul 11, 2011)

what do you mean slim keys?


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## LAN_deRf_HA (Jul 11, 2011)

Like laptop keys. Once you go slim it's hard to go back to tripping over those old clunkers...


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## BumbleBee (Jul 11, 2011)

you don't have to press a Cherry MX switch all the way down like a rubber dome. 

Cherry MX switches travel 4mm but actuate at 2mm. 

a scissor switch like in a laptop travel 2-3.2mm.


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