Keyboard PS2/USB Question

Garido · 7 Feb 2011 at 11:12

Firstly sorry if this is in the wrong place.

Hope you folks can help bust a myth but someone once mentioned to me that PS/2 was better for keyboards as it allowed multiple inputs at the same time whilst USB was limited. Is this true or not?

Secondly, does this go for mice as well. I hear the sampling rate is higher for mice through USB than through PS/2.

predator70 · 7 Feb 2011 at 11:24

never noticed any difference. I would personally recommend using a usb keyboard and mouse

Garido · 8 Feb 2011 at 02:35

Still trying to find if there is any truth to the myth that PS/2 allows more strokes at the same time compared to USB.

Werewolf · 8 Feb 2011 at 02:53

It all depends on the controller chip and layout of the connections in the keyboard, I think the issue with USB keyboards was that in the early days especially some manufacturers used to use skimp a bit.

It's actually all down to the way the keyboard keys are hooked up to the controller, as it's done (from memory) in grids with different keys in different connection grids, and the problem comes when more keys on the same "grid" (usually ones near each other) are pressed than the controller allows (the way to work round that is to have keys that are commonly pressed together on separate grids as much as possible, or a better control chip).
The problem is, having more of the connection grids, and a better chip adds to the manufacturing price, so the cheapest boards tended to be optimised for normal windows usage where you might only have say 2 of modifier keys (ctrl, alt etc) and one or two of the normal keys pressed at once - not good for gaming where you might have ctrl, space, w and a pressed together to do a crouching diagonal strafe.

IIRC most keyboards, even the cheapest can usually take 3-4 keys together, some can take several more but dependant on which ones exactly.
Keyboards sold as "gaming" or higher priced ones are usually optimised to allow the most keypresses possible, taking into account not just normal use but the commonly used keys for games (things like WASD, shift, ctrl, alt and space) and have the electrical connections wired up to allow for them to be pressed in combinations of 3-4 at once.

The Mouse thing was certainly true back in the early days of USB1, and I think even today potentially if you're using the mouse on the same USB controller as say an active USB HDD or similar bandwidth hog (all devices on the same controller share the bandwidth), but not if you either use the controller just for the usb keyboard/mouse or with other low bandwidth things (like game pads etc).

Sorry if my explanation is vague, i'm rather tired

[edit]
I don't think I've ever had any issues with any of my keyboards, but I don't think I've ever used the absolute cheapest ones for any serious gaming.

Garido · 8 Feb 2011 at 03:01

Very informative explaination so cheers.

In the end it matters on the controller, not the interface. If only there was a way to find out how many keystrokes a keyboard could have at the same time.

Werewolf · 8 Feb 2011 at 03:14

Aye, it's pretty much down to the physical electrcial connections on the keyboard, and the controller chip used.

I think some manufacturers do specify how many keys can be pressed, but it's a fairly safe bet that any keyboard sold as a gaming one will have more than the basic number of concurrent key presses for the common keys.
I think the biggest problem is when you try and use multiple keys on the same row at the same time.

[edit]
I Found this little demo on the MS site

Garido · 8 Feb 2011 at 03:20

Werewolf said:
Aye, it's pretty much down to the physical electrcial connections on the keyboard, and the controller chip used.

I think some manufacturers do specify how many keys can be pressed, but it's a fairly safe bet that any keyboard sold as a gaming one will have more than the basic number of concurrent key presses for the common keys.
I think the biggest problem is when you try and use multiple keys on the same row at the same time.

[edit]
I Found this little demo on the MS site

I'm gutted to find my G15 only having 6 strokes but even then it's hit and miss. Thanks for the link.

BRILLIANT POST. THANK YOU SO MUCH.