Motherboard Forms

AT & Baby AT
measures 12" X 13.8" - baby measures 13" X 8.7"
only has a keyboard connector
2 power cables connect to the system board P8 & P9 connectors
power supply provides 5 volts dc, and 12 volts dc to the system board
cpu sits in front of expansion slots, long cards don't fit

ATX & Mini-ATX
measures 12"X9.6" - mini-ATX measures 11.2"X8.2"
most common form factor
cpu and memory slots sit beside expansion slots
power supply blows air into case to processor
soft switch or soft power available (An OS can turn off the computer)

LPX
designed for slimline desktop style computers
uses a riser card in the middle of the system board, which holds expansion slots
riser card does not have built-in ports for audio, joystick, usb, network, and modem

NLX
designed for slimline desktop style computers
uses a riser card on the edge of the system board
riser card may have built-in ports for audio, joystick, usb, network, and modem