The PC1640 inherited several distinctive design choices from the PC1512. The power supply was integrated into the monitor rather than the main unit, allowing for a more compact system case. A physical volume control on the internal PC speaker let users adjust or mute the beeper from boot — a feature still absent from most modern PCs. The keyboard included an Atari-compatible joystick port that mapped movements to keyboard codes, enabling compatibility with many DOS games written for keyboard control.