Motherboard form-factor used by ”branded“ PCs like Compaq. The main feature of LPX motherboards is the lack of slots. The slots are located in a separated board, called backplane, which is plugged to the motherboard through a special connector. The idea is to allow the design of thin PCs, since on this kind of motherboard the expansion boards aren’t perpendicular to the motherboard but parallel.
LPX motherboards measure 8.66“ x 13“ (22 cm x 33 cm). There is a smaller LPX form factor called Mini LPX, which measures 10“ x 8.5“ (25.4 cm x 21.8 cm).
Visually speaking it is easy to differentiate an LPX from an NLX motherboard. On LPX form factor the backplane connector is located in the middle of the motherboard and this connector looks like an expansion slot (female connector). On NLX form factor the backplane connector is located on one of the motherboard edges and it is a 340-pin edge contact male connector, similar the one used by expansion boards.
click to enlarge
Figure 1: LPX Motherboard.