A motherboard form factor used in some desktop model PCs. The distinguishing characteristic of LPX is that expansion boards are inserted into a riser that contains several slots. So the expansion boards are parallel to the motherboard rather than perpendicular to it as in other common form factors, such as AT and ATX. The LPX design allows for smaller cases, but the number of expansion boards is usually limited to two or three.
The LPX form factor is gradually being replaced by NLX.