What is keyboard ghosting?
Check how many keys your keyboard can register at the same time and whether it drops keys in gaming combos. Hold several keys at once and a full on-screen keyboard lights up every key it receives. The test records your maximum rollover and ticks off combos for FPS, MOBA, rhythm, typing and arrow-key games. It also flags key chatter (one press registering twice) and logs every press with its hold time. If a key never lights up while others are held, your keyboard is blocking it.
Keyboards wire their keys in a grid of rows and columns. When three keys that share rows and columns are held, a cheap keyboard cannot tell which keys are really down, so it either reports a key that was not pressed (a ghost key) or, more often on modern boards, blocks the extra key entirely. Rollover is the number of keys a keyboard can report correctly at once. Gaming keyboards add diodes or use different scanning so every key is read independently, which is called n-key rollover or NKRO.
