Broadly speaking, the motherboard or mainboard centralizes all hardware components of the computer.

It is in charge of connecting them to the CPU and delivering power to some of its internal components and even external devices.

But the motherboards’ functions go beyond that. They are designed for managing how these components communicate while supporting many of the computer’s features we take for granted.

Motherboards have been part of PC’s since the eighties.

Prior to the use of motherboards, computer components were connected by a backplane.

The backplane allowed components to interact with each other.  The motherboard, on the other hand, introduced the concept of giving its own processing capabilities to this kind of board, including native support for things like mice and keyboards.

The introduction of the motherboard coincided with the standardization of PC components and compatibility.

The iconic 1981 IBM Personal Computer was the very first one to come with a motherboard.

This computer design was cloned by other manufacturers, leading to the general compatibility among computers we know today.

Also, in this same decade, Apple’s Macintosh featured a “logic board” which is basically a motherboard. To this day, Apple still maintains this name for their motherboard.

The form factor for motherboards was taken from IBM as well.

The AT motherboard, introduced in 1984, set the standard for desktop PC’s and would be replaced in the nineties by IBM’s ATX, which is still the most common size for desktop computers.

Today motherboards can be found not only in desktop PC’s and laptops, but also in smartphones and tablets.

Despite ATX being the industry standard for motherboards, there are other smaller variations for desktop PC’s such as micro-ATX and mini-ATX, and also for mini-PC’s, like the UCFF form factor present in most Intel Nucs.

Most motherboards include sound and network capacities, as well as integrated graphics.

These are features that in the past required additional hardware, yet are now included in the motherboard for functionality that is essential for most users.

Of course, in the case of computers for professional audio or video editing, or even gaming, the computer is usually going to need adequate additional hardware to perform those functions.

Let’s take a look at an ATX motherboard.  Check out the video at the top of this blog post for a visual representation of the following information.

If you have never seen one, it may look chaotic, but its hardware slots and components are easy to identify.

Starting with the regular hardware connectors, we have the CPU socket for our processor and the memory or DIMM slots for our RAM modules.

The bus slots, for their part, can be used for improving the PC’s capacities or adding certain features.

There are also PCI and PCI Express connectors, which come in different versions and sizes for different card types, and can be used for things such as video and sound cards, network cards, and USB port expansion.

There are also the SATA ports. This is where you would connect most storage drives. Aside from storage, SATA ports can also be used for CD, DVD, or Blu-ray drives.

Aside from the slots used for internal hardware components, motherboards also have a set of ports for input and output connections: USB ports, audio outputs, video connectors like VGA or HDMI, and network ethernet ports.

These ports are normally located on the part of the motherboard at the back of the case. However, motherboards also provide support for frontal USB ports and audio output. These are connected to the motherboard by headers or male pin connectors. There are headers for the case fan, for the frontal led lights and for the powerup and restart buttons.

Depending on the motherboard, the communication between the PC components and the CPU can be managed differently.

Older computers had a chipset for this job, divided into the northbridge and the southbridge.

The northbridge connects the CPU to the RAM and PCI Express bus slots. These are components that need the highest data transfer speed.

Since the northbridge manages the speed of these components, it is often adjusted for overclocking purposes.

The southbridge is in charge of the rest of the PC components, that is, ports like PCI slots, SATA connectors, USB, audio, and peripheral devices like the mouse and keyboard.

For the processor to communicate with the southbridge and its components, it has to go through the northbridge.

Newer motherboards have somewhat abandoned this dual chipset system by integrating the northern bridge functions into the CPU itself.

The southbridge has been replaced by the chipset itself, named Platform Controller Hub, in the case of Intel, or simply “the chipset” for AMD.

So far, we have talked about the hardware properties of motherboards. Yet motherboards have a software part too, known as the BIOS.

The BIOS is permanent software programmed into read-only memory, otherwise known as firmware.  It contains all the code for managing the boot, or startup process and many of the hardware devices.

Different motherboards have different BIOS interfaces and some BIOS allow more control over the hardware than others. Also, the BIOS checks the state of its hardware components: things like CPU temperature and voltages, the cooling fans, and more.

Depending on the motherboard, the BIOS ROM chips can be connected to the northbridge or CPU, or the southbridge.

For storing information like the date and BIOS configuration, motherboards have their own internal battery called the CMOS battery.

Motherboards also come with troubleshooting features for hardware errors such as sound beeps, led lights, or text message systems.

Now, these are the general specifications for most motherboards, but there are of course certain motherboards for certain tasks.

Some motherboards come with many PCI Express x16 slots and allow using two or more video cards combined. On the other hand, server motherboards lack desktop features like onboard audio but instead have extra CPU sockets and ram slots, as well as better support for network administration.

In this sense, certain motherboards are limited to certain hardware they can support. This is especially relevant if we consider the motherboard’s aging potential.  For example, the type of SATA or DDR hardware we can use with it may not be the newest nor the best.

Recent M.2 type storage drives require a specific M.2 form factor for connecting to the motherboard that not all of them have.

Still, the most challenging aspect of a motherboard in this regard is the CPU.

CPU socket types changes periodically, limiting the possibility of upgrading an old motherboard with a new generation CPU.

In this sense, the lifespan of a computer for a certain task is fixed to the upgrade possibilities of its motherboard.

When understanding how a computer works, motherboards are important.  The next important thing to understand is Processors.