What is LPX Motherboard? – Learn Here

Last Updated on November 6, 2020

It’s safe to say that many people are impressed by small and compact desktop computers that can still handle the work that’s thrown at them. Low profile desktops are ideal for people who like to minimize space usage without sacrificing the functionality and efficiency of their computers.

While there are many slim and compact motherboards today, some even measuring just a little above the size of an average credit card, a few years ago, things were a little different.

So what is LPX motherboard? Basically, LPX was a form factor that quite famous during the late 80s and 90s because it promoted a slim PC build. Its main attraction was the use of Riser Card to add functionality.

However, due to the heat dissipation issues caused by the late 90s processors, the LPX form factor started to lose its turf to ATX form factors which promoted good airflow.


Also Read: What is VRM on Motherboard?

What is Motherboard Form Factor?

What is motherboard form factor
The different types of ATX forms factor most commonly found. The ITX series of MOBOs are also quite common.

Whenever the shape of a motherboard, its size, and placement of components on its surface comes to mind, the form factor is the term used to describe the features.

Form factors determine a lot of things in a motherboard such as the size of case you can get for it, the kind of power supply it can use and in many cases, the number of peripheral components you can fit into it.

While there are multiple form factors, from very large ones like the EATX to some really small ones, a very unique form factor is the LPX.

Read in Detail: What is Motherboard Form Factor?

What is LPX Motherboard?

What is LPX Motherboard
As seen here, an LPX motherboard with riser slot.

At a time when computers were still bulky, Western Digital, the company most people are familiar with for their cutting-edge storage devices, came up with a way of reducing the height of a motherboard setup; and the LPX motherboard was born.

LPX stands for Low Profile extension and it was a fairly popular form factor during the late 80s and the 90s. It’s main attraction was the use of Riser Cards (daugtherboards) that were further used to add expansion capability to the PC.

The form factor of the motherboard allows the overall PC to be smaller than the average in the 80s and the 90s. Users who wanted a less bulky stack could opt for an LPX motherboard and in turn, get a device that fits in a low profile case and could still perform just as well as other motherboards at the time.

One important point to note is that unlike the form factors of today that have specific and standardized dimensions, LPX motherboards never truly had a standardized dimension, however, most were built with 13×9 inches dimensions.

Riser Card

Riser Card
A Riser Card, such as the one shown, is inserted on the LPX motherboard to add functionality. The Riser Card had the PCI expansion slot as well as support for older ISA cards.

This is a component that we don’t see in many modern motherboards today. A riser card is a circuit board that gets plugged into a special slot in the motherboard of a computer.

It offered many advantages, the most important being that it had several additional slots for expansion cards.

With just one slot on the motherboard, users could plug in a riser card and immediately get the chance to add two or more expansion cards, like video card or sound card, to their computer.

Because the riser card stands perpendicular to the mainboard, all expansion cards plugged onto the riser card sat perpendicular to the surface of the motherboard.

In contrast, most expansion cards today go into PCIe slots that are perpendicular to the board, so the cards stick out upwards from the motherboard. With a riser card, the expansion cards lay parallel and hence made the overall height of the PC much smaller.

Besides providing additional expansion slots, they save a lot of space in the height department, hence making LPX motherboards slimmer than many other form factors.

Features of an LPX Motherboard

When it was first developed in 1987, the motherboard measured 9 Inches by 13 inches in size and could fit in slim cases.

Its configuration included serial, parallel and video connections as well as a PS/2 port that was placed differently from other motherboards. However, the most unique feature was that the motherboard made use of a riser card for extra components like expansion cards.

The Mini LPX version of the LPX board was developed later and had an even smaller width that was 2 inches smaller than its predecessor.

This meant that users could fit the device into even smaller cases when needed.

Riser cards provided users with the ability, although limited, to maintain and upgrade their computers by installing expansion cards for features they needed.

The only problem with this was that the size of the riser card often limited the number of expansion cards that one could install and hence often users would only have two or three at most.

Advantages of LPX Motherboards

The greatest advantage of this form factor was that it saved a lot of space at a time when computers could get tall and bulky.

With the expansion cards lying parallel to the motherboard, the height of the PC components could be reduced significantly.

Although it couldn’t support many expansion cards, the motherboard had enough lanes on the riser card to support two or three expansion cards with just the single slot that the riser card plugged into.

This was beneficial as you did not need to have multiple ports and slots on the motherboard itself.

Disadvantages of LPX Motherboards

Due to the form factor’s implementation of a riser card, LPX motherboards were not friendly for home pc builders.

Many components were being fixed into really small spaces, making the overall build cramped and difficult to work with, let alone maintain a neat-looking build.

Since the motherboards were small and the riser cards ran the expansion cards in parallel with the motherboard, air supply between the components was at times limited resulting in inefficient cooling.

This form factor offered very few options in terms of upgradability. It was not the standard at the time so you needed very specific components for it to work with.

Also, the limited expansion card slots meant that users who needed extra slots for additional expansion cards would be forced to get a motherboard with more slots.

As advantageous as it seemed, this form factor came to be replaced by modern ones which improved upon many of the things that the LPX motherboard was coming up short on.

Nail in the Coffin for LPX Motherboard

LPX Case
LPX motherboard could be fitted into small cases. They usually sat horizontal instead of vertical as we see with PCs of today. These were the original “low-profile” cases.

As mentioned earlier, the LPX motherboard had a major issue with cooling.

Back when the LPX motherboard was introduced, the processors of the time ran fairly cool. Therefore, an enclosed PC build with expansion cards running parallel to the motherboard, as promoted by LPX, did not pose much of an issue.

However, with processors getting better and hotter, the enclosed LPX build introduced an important issue of airflow. This happened during the time of Intel Pentium II in 1997, when the processor technology had become too advanced and too hot for a small enclosed space.

The processors now needed a motherboard form factor that promoted good airflow and LPX was just not cut out for that. This, in turn, paved the way for ATX and ITX form factors, that we see in use today, where the expansion cards run perpendicular to the motherboard instead of parallel.


People’s fascination with slim computers is not a new phenomenon. Back when they were still building computer motherboards, Western Digital came up with the LPX motherboard as a solution for low-profile PC users.

So what is LPX motherboard? As was seen, the LPX motherboard could fit in a shorter case and still manage to pack a punch in terms of performance.

Its riser card provided access to multiple expansion card slots and allowed the expansion cards to plug in parallel to the motherboard. I

Unfortunately though, a lack of proper air flow for the more advanced processors of the late 90s lead to their demise.


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