 The IIe also switched to using newer single-voltage 4164 DRAM chips instead of the unreliable triple-voltage 4116 DRAM in the II/II+.For this reason the motherboard design is much cleaner and runs cooler as well, with enough room to add a pin-connector for an (optional) external numeric keypad.Also added was a backport-accessible DE-9 joystick connector, making it far easier for users to add and remove game and input devices (previous models requiring plugging the joystick/paddles directly into a 16-pin DIP socket on the motherboard; the IIe retained this connector for backwards compatibility).