NLX Form Factor

NLX is intended for low-profile PC’s. NLX systems uses a riser board, similar to the LPX form. The riser boards sits vertically in the case and is connected directly to the power supply. Each of the expansion cards connect directly to this riser board, as well as the HDD and FDD connectors that usually reside on the motherboard itself. So, basically, the riser card is the hub of the NLX system, with everything connecting to it. Even the NLX motherboard can simply be removed from its slot on the riser card and replaced.

An NLX motherboard looks different than that of AT of ATX. The first thing you’ll notice is that it has no expansion card slots nor does it have any drive connectors. As said before, all this has been moved to the riser card. Also, you will notice a 340-pin connector on the side of the motherboard. This is what interfaces with the riser card. Like ATX, the I/O connectors are on a panel on the rear of the board, and like ATX, this part of the board sticks out of the case so you can connect your USB, parallel and serial devices to the NLX system.

The power supply looks similar to that of an ATX machine, and connect to the motherboard via a 20-pin connector. It has a single exhaust fan which happens to be also placed near where the CPU is placed on the motherboard, so that the power fan can help cool the NLX system.

LPX Form Factor

LPX is like an older AT-version of the NLX form factor. LPX motherboards have the same, if not smaller, dimensions as a baby-AT motherboard. They also share the same AT-style power connectors: two 6-pin connectors usually labeled P8 and P9. Like NLX, it uses a riser card as the hub of the system. The external I/O ports on an LPX system follow the same format usually: (from left to right) VGA, parallel port, 2 serial ports, PS/2 mouse, PS/2 keyboard. Some newer versions alter this layout to accomdate USB and possibly LAN connections.

LPX, back in its day, was taken on by several manufacturers, and it was used pretty much up until the Pentium II days. But, with the lack of standardization, it did not go beyond that. LPX riser cards had to meet certain electrical requirements, but beyond that, the arrangements of the various connectors varied from manufacturer to manufacturer. This led to difficulty in upgrading because you could not just swap out riser cards. Thus, it had a limited life.