A computer buyer’s guide: The motherboard

Okay, so the previous installment of my guide on how to choose the best processor was a bit long and I hope none of you readers pulled your hair out in frustration. To make amends, I’m going to make this one a bit shorter and easier.
At first, I thought I should tackle this subject from a different angle, but then I realized that that approach wasn’t the best and the resulting draft was a bit all over the place, seeing how it delved into technical details like what a southbridge is and other nasty, nasty stuff that the average reader of this blog doesn’t want to hear about.
Instead, I’m going to strive for simplicity by simply talking about motherboard sizes, their sockets and the connectors you can find on them. This article is going to be of interest to you even if you’re planning on purchasing a laptop, which is why I’m listing the connectors first, then the sockets and at last the sizes. If that’s your case, you can read the first part and completely skip the second and third.

External connectors

USB 2.0

You’re surely familiar with USB 2.0: it’s by far the most common connector in existence and for good reason: name a device that attaches to a computer and chances are it uses USB.
Its shape is rectangular and the plastic piece inside of it is usually dark grey in color. This color is important because it helps telling it apart from USB 3.0 and 3.1 ports, which use a different color.

USB 3.0

Identical in shape to USB 2.0 ports, they differ from their previous-generation counterparts in their color. In this case, blue. USB 3.0 is theoretically capable to attain tenfold speed improvements over USB 2.0. For this reason, it’s suggested you plug high speed devices to 3.0 ports (like external hard drives) and any other device to 2.0 ports.

USB 3.1 Type A

Yet another USB revision, USB 3.1 promises theoretical speeds of up to 10 Gbps, double those of USB 3.0. These ports are still rare and devices that require them are even more so. There is currently no standard for its color coding. They use the same header as USB 3.0.

USB 3.1 Type C/Thunderbolt 3

USB 3.1 Type C is another form factor for USB 3.1, roughly the same in size as the micro USB connector commonly found on smartphones for charging and connecting to a computer. It promises to provide USB 3.1, Thunderbolt, PCI Express and DisplayPort through a single connections. Cables and devices for it are still crazy expensive and very few motherboards support it.
It was notably featured on the 2016 Macbook as the only connector on that machine.

Thunderbolt 2

Thunderbolt is commonly associated with Apple computers, although a few other manufacturers produced computers that use it. It’s identical in shape to the mini DisplayPort connector, with which is also compatible (the Thunderbolt port doubles as a monitor output).
Thunderbolt devices support transfer speeds of up to 10 Gbps per channel and, although more expensive, they’re usually faster than their USB 3.0 counterparts. Additionally, you can daisy-chain up to 6 Thunderbolt devices to the same port on your computer.


This is probably the oldest connector still commonly in use today. It’s used for connecting a keyboard (purple connector) and a mouse (green connector) to a computer. More recently, motherboards started featuring only one of those connectors, because the need for it has been steadily declining. We’re all glad PS/2 is dying because the pins on the connector bend far too easily.

Note: If your keyboard or mouse are connected through PS/2, do not remove them while the computer is still on. Doing so can damage your device, connector, or motherboard.


VGA ports connect your motherboard to your monitor and provide video output. They’re usually blue, sometimes black, and feature 15 pins and two screw holes to lock the connector in place.


DVI connectors are similar to VGA, but they’re longer and usually white in color. Their plugs are also squared (as opposed to rounded) and you’ll find a “cross” on one of its sides, used to send analog data. You can think of them as HDMI without audio. Similarly to VGA connectors, DVI plugs feature thumb screws to hold the connector in place.


HDMI is becoming steadily the most common type of connection. Not only does it support higher resolutions than VGA does, but also allows audio to be transferred to your monitor using only one cable.

Internal connectors

USB 2.0 header

Your motherboard manual or spec sheet may list some ports as “mid board ports”. What this means is that they aren’t found on the rear, but instead a special 9-pin connector, called header, is provided to connect additional ports found on the front of your case or on a plate (sold separately) that takes up one of your expansion slots.

USB 3.0 header

The USB 3.0 header is blue in color, features 20 pins and is about three times as big as a USB 2.0 header.


SATA connectors are designed to connect hard drives, solid state drives and optical drives to your motherboard. There are three revisions of SATA, named SATA 1 through 3, but they share the same connector type and the same type of cable can be used on all three revisions with no performance loss. SATA 1 is now practically extinct in the wild, but some motherboard may include a mixture of SATA 2 and SATA 3 ports, usually color coded. As there is no standard for SATA ports color, you’ll have to refer to your motherboard’s manual to know which one is which.

RAM slots

These elongated slots are where your RAM modules will sit. We will discuss them in-depth in a future article.

PCI Express

PCI Express (or PCI-E) slots are commonly found on the lower half of the motherboard and they’re used to add expansion cards to a computer. They come in 2 main variants, called x16 and x1. These numbers refer to the speed at which the slot operates: generally, x16 slots are used for high-performance devices such as graphics cards and PCI-E SSDs, whereas x1 slots are for less performing devices, like USB cards, sound cards, network adapters, and so on.

PCI-E x16 slots sometimes have a lock that prevents the card from moving, since this technology does not support hot-plugging, meaning that a complete system shutdown is required before installing or replacing a PCI Express device.


PCI is the grandaddy of PCI Express. It’s easily told apart from its successor because it’s shorter than a x16 slot, longer than a x1 slot, thicker than them, and never has a lock. PCI is considered a legacy technology and as such is becoming less and less common.


Now that the laptop people are gone, we can talk behind their backs. They smell like butt.
With that out of the way, let’s discuss what a CPU socket is and does.
A CPU socket is the component where your processor sits on your motherboard. It’s easily told apart from other components by the fact that it’s squared and a lever is next to it.
AMD and Intel processors cannot use the same types of sockets, and even products from the same manufacturer may use different sockets.
Intel’s most recent desktop sockets are called LGA 1151 and LGA 2011-v3, whereas AMD sockets are called FM1, FM2, AM1, AM2, AM2+, AM3, and AM3+. To know what socket your chosen CPU uses, head over to Intel Ark or the AMD website and search for the model name.


There are three common motherboard sizes available in the market today. These mainly determine how expandable your computer is going to be, how many ports on the rear I/O area you get, and what cases it’s going to fit in.
The biggest of them all is the ATX form factor. ATX motherboards measure 305 x 244 mm and include multiple expansion slots (up to 9), more SATA connectors, and 4 RAM slots (or even more). An ATX motherboard requires a bulky case to be installed in and is usually too space-consuming for an office computer.

Micro ATX is a variant of ATX that does away with some expansion capabilities (up to 4 PCI Express or PCI devices) in order to fit in smaller case. Generally, they’re similar feature-wise to ATX motherboards, which makes them ideal for an office build.

Lastly, Mini-ITX is the smallest motherboard form factor available to consumers, which allows for smaller computers at the expense of expandability. Mini-ITX motherboards generally feature only 2 RAM slots (sometimes requiring SODIMM modules), 1 PCI Express slot, and 2 SATA ports.

About Andrea Luciano Damico 137 Articles
Andrea Luciano Damico is a freelance translator from Italy. Among his interests are linguistics, technology, video games, and generally being a chill guy. He runs Let's Translate.it and Tech4Freelancers.net.