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I've been experiencing a problem with my keyboards lately. I own an Alienware laptop M11x. I've attached a USB Trust keyboard first and experienced some problems while playing FIFA 12. Namely: When the Left and Up buttons are pressed I cannot press one of the buttons S, G, B, N, H. S is very important since it's my pass button.

So I took the keyboard back and bought a Microsoft Keyboard 600. Alas, the problem still persists. I must say that for instance I can press 4 buttons like: A S D F and it will work like a charm.

Update: I must say that that particular problematic combination works on my laptop keyboard and it persists over the whole system.


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migrated from Feb 2 '12 at 21:44

This question came from our site for passionate videogamers on all platforms.

Problem persists overall – AlexRednic Feb 2 '12 at 21:41
up vote 4 down vote accepted

It's call n-key rollover. It controls the total number of keys that can be pressed at one time on a keyboard before the controller stops recording new keypresses.

Usually, you'll only find full n-key rollover on high end keyboards. Normal or low-end keyboards will generally have a limit after which the keyboard controller will stop recording. As your key sequence is 8 keys long, you're probably well over the limit.

Wikipedia has an article with a few more details:

If you really, really need a key combination this long for your kick move you'll need to try a keyboard that specifies full n-key rollover as a feature to ensure that the keyboard will always be able to handle every key you press all the time.

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I probably didn't express myself correctly: when I hold Left and Up arrow keys pressed I cannot press one of the keys: S, G, B, N, H. That makes it a 3 key combination – AlexRednic Feb 2 '12 at 22:00
Which means your keyboard is an average keyboard that only handles three simultaneous presses. Gaming keyboards may offer a higher number without being full n-key capable. – music2myear Feb 2 '12 at 22:09
Note that n-key rollover is only possible using PS/2. The max with USB is, I believe, 6-key rollover (excluding modifiers). – BlueRaja - Danny Pflughoeft Feb 3 '12 at 1:07
@Alex: I think music2myear means to say it can only handle two simultaneous presses; that's pretty typical of normal, low-end keyboards. The cheapo HP keyboard I have at work does exactly the same thing - if I hold Up and Left, I can't use any of those keys you mentioned. The NKRO (n-key rollover) keyboard I have at home though (obviously) does not have this problem. – BlueRaja - Danny Pflughoeft Feb 3 '12 at 1:15
Thank you for the correction @BlueRaja. What NKRO keyboard do you use? – music2myear Feb 3 '12 at 14:50

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