Not all computers come equipped with all the ports needed to fully optimize the power of the Das Keyboard’s n-key rollover (aka NKRO: a user can press any number of keys and have them *all* registered by the computer, no matter how many keys are being held down at once). We recommend Syba’s SD-NECPS-2U2PS2 card to add two PS/s ports to your PC  (for full n-key rollover), with the added bonus of two added USB 2.0 ports. Check out the pic below (taken straight from, click this link to purchase). Happy gaming.