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Results: Ghosting And Key Rollover

Four Keyboards And Four Mice For LAN Party Gamers, Rounded-Up
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Of our tests, the ghosting and key rollover metrics are probably the most applicable to gaming. Microsoft's Applied Sciences Group does a particularly good job of explaining the phenomenon of ghosting:

"Ghosting is the problem that some keyboard keys don't work when multiple keys are pressed simultaneously. The key presses that don't show up on the computer or seem to have disappeared are said to have been "ghosted". On most keyboards, even some that are explicitly marketed as "Anti-Ghosting," this happens with many three key combinations. Imagine playing your favorite video game and not being able to, say, run diagonally and fire your weapon at the same time (say pressing a, w, and g simultaneously). This is a result of the internal design of most existing keyboards...

Typically, ghosting is the result of one or more of following three limitations: the hardware can't read the given key combination, the software on the computer doesn't support multiple simultaneous keys, or the communication protocol between the hardware and software limits the maximum number of simultaneous keys reported."

Source: Microsoft Applied Sciences GroupSource: Microsoft Applied Sciences Group

In the image above, from the same Microsoft Applied Sciences Group blog, each row and column intersection corresponds to a key. Ghosting surfaces as a problem when the keyboard cannot distinguish which combinations of rows and columns are being shorted, which would otherwise register as a keystroke. You can see how pressing just one or two keys would be easy to interpret. Hitting three keys gets problematic, however, when the third key shares a row and column.

Key rollover is inter-related in that it measures the number of keys that a board can register at a time. Typically, USB keyboards are able to register six regular keys. A keyboard offering true n-key rollover is able to overcome such limitations and recognize any number of key presses correctly.

For each board, we held down combinations of three (and then all four) W, A, S, and D keys, while pressing each of the other test keys in succession. Only the Siig board had trouble with W, A, S, D, and combinations of Tab, Caps Lock, Shift, and Control. All of the keyboards, except Razer's, had trouble once we introduced the number keys. For example, Logitech's K800 would not register 7, 8, 9, or 0 with either W, A, D or A, S, D depressed. Similarly, Kensington's solution had issues with '~', 1, and 2, plus various auxiliary keys like Q and Z. 

Further, Siig's JK-US0412-S1 exhibited the worst issues with ghosting. It wasn't able to register W, A, S, and D at the same time. Pressing A, S, and D blocks W, while W, A, and D block S. In fact, the keyboard wouldn't even recognize the fairly common combination of Q, A, and W. These results certainly call into question the board's utility as a gaming peripheral.

The BlackWidow had almost no trouble in this test. We say almost because the board has a specific gaming mode. When that isn't activated, it can be tripped up. The only advantage to using standard mode is that the Windows key remains enabled, so we'd be inclined to leave gaming mode on most of the time. With it active, we ran into zero issues with ghosting and observed 12-key rollover, even though Razer only claims 10-key performance. These impressive results certainly support the enthusiasm surrounding mechanical keyboards right now.

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