If you’re in the market for a mechanical keyboard, you’ll likely come across the term “N-key rollover.” You might also see it written as “NKRO.” You’ll definitely get the impression it’s a good thing to have because it’s the kind of thing marketing departments like to shout about.
But what is N-key rollover? And when and why is it a useful feature to have in your mechanical keyboard?
What Does N-Key Rollover Do?
Before we even look at what rollover is, let’s get straight to the point. If your keyboard has N-key rollover, then every single key you press is registered as a separate input—no matter how many keys you press.
Rollover essentially refers to how many keys you can press at the same time before you run into problems. Cheaper keyboards don’t have unlimited N-key rollover. Some may have as little as two-key rollover, while most good keyboards will have at least six-key rollover.
What Happens If You Exceed Keyboard Rollover?
A couple of issues can occur if you press or hold down more keys simultaneously than your keyboard can handle.
One is blocking (also known as jamming), where some keys are simply ignored. So, for example, let’s say you have a keyboard with five-key rollover. You open a text file and press the number keys from one to six simultaneously. Instead of seeing six numbers, you’ll see five because one of the keys is blocked.
Another problem you might encounter is ghosting. This is where a key you didn’t press is registered as an input. In our example, you might see an eight on the screen, even though you never pressed that key.
With N-key rollover, these issues never occur. For example, press six number keys, and you’ll see six numbers on the screen. Press 20, and you’ll see 20 and so on, depending on how many keys you can press at the same time without doing yourself an injury.
You can test your own keyboard’s rollover using web tools like Microsoft’s keyboard ghosting interactive demo.
Is N-Key Rollover Actually Useful?
That’s the million-dollar question. Obviously, ghosting and blocking are bad, but do you really need N-key rollover to prevent them?
Certainly, if you’re a gamer, an advanced typist, or a fan of typing games, limited key rollover could be a problem.
Let’s say you’re playing a PC game. You could be pressing Shift to run while also holding down W and A to move diagonally forward. You might then press Space to jump and R to reload. You’re already up to five keys held down on the keyboard with one hand.
If your other hand isn’t on your mouse, you might then bring it over and press an F-key to unleash a quick action or spell. But your keyboard has five-key rollover, so this sixth key isn’t registered at all.
Your enemy kills you, and it’s game over.
But is this a common problem? Possibly not. Once you get over 10-key or even six-key rollover, is there really any benefit to going further than that? Surely you’re never going to need to press every key on your keyboard at the same time?
So Do You Need N-key Rollover?
In a word, no. If your keyboard has it, then it’s certainly not a bad thing, but it’s not something you should use as a deciding factor when choosing a keyboard. You definitely shouldn’t pay extra for it.
Other features are far more important, like how comfortable a keyboard is to use, how much noise the mechanical keys make when you press them, and whether keys light up, along with gaming features, like macro keys.
So, if you find a mechanical keyboard you like, and it has 20-key rollover, 100-key rollover, or something similar, don’t rule it out. Ultimately, the best thing about mechanical keyboards is how they feel when you type or game on them—not how many keys you can press at the same time.
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