Motherboards Explained: What Are ATX, MicroATX, and Mini-ITX?

A bare ATX gaming motherboard.MSI

The standardization of hardware is one of the major assets of desktop computers. You can mix and match parts to your heart's content. But not all motherboards have the same physical size. There are different form factors for different types of PCs.

Different standards

Like other PC components, motherboards have standardized form factors, including ATX, MicroATX, and Mini-ITX. Almost all the motherboards for personal computers at your local computer store or online will be in one of these varieties.

Standardization means that you can easily find a processor, RAM, power supply and storage compatible with your motherboard. It also opens the choices for desktop PC cases. Many cases support the three main motherboard sizes. The mounting points are drilled at the appropriate locations and adequate space is available for the rear ports and the input / output shield that covers them.

This is a nice thing, but to decide which motherboard is best for you, you need to consider factors such as space and your PC building experience and performance.

PC Motherboards: The Essential

A Ryzen B450-M motherboard bare.The Asus Prime B450M-A MicroATX motherboard for AMD Ryzen processors. Asus

Intel created the ATX form factor and introduced it for the first time in 1995. For nearly 25 years, ATX design has been the predominant form factor for home and office computers.

The largest of the three motherboard sizes we review, the ATX measures 12 inches by 9.6 inches. The specification requires all ATX motherboards to be of this size. It also specifies the locations of the mount points, the I / O panel, the power connectors, and all other connection interfaces.

All of these features are crucial for any motherboard. The mounting points keep the motherboard away from the metal surface of the enclosure to prevent short circuits. The I / O panel and the shielding provided allow you to access the rear ports of your PC for displays, audio and USB port. Then you have the power connectors and all the other interface points that need to be located at predictable locations to help the system builders.

However, not everyone wants a motherboard the size of an ATX, especially if its goal is to make something more compact. Enter, the MicroATX cards, which measure only 9.6 inches by 9.6 inches. As with larger ATX motherboards, the standard determines what all critical points should be.

Finally, the Mini-ITX, developed by Via Technologies in 2001, is the smallest of all, measuring only 6.7 inches by 6.7 inches.

ATX motherboards are the most scalable. They typically have six (or less) PCIe slots for items such as graphics, sound, and network cards. However, there are Extended ATX (or EATX) cards with seven PCIe slots, but these are for enthusiasts and servers and are beyond the scope of this article.

The MicroATX can have up to four PCIe slots, while the Mini-ITX only has one for a graphics card.

RAM is also limited on the Mini-ITX. It can only accommodate two slots against four on ATX or MicroATX cards. This does not mean that Mini-ITX cards do not have enough RAM. For example, if you want 32 GB of RAM, you only need to put two 16 GB modules, while for the other two motherboards you fill up with 8 GB modules.

Motherboards: when to use what

A bare Mini-ITX motherboard with two RAM slots and one PCIEe slot. A gaming motherboard Gigabyte Mini-ITX. gigabyte

These three types of motherboards work with almost any type of home PC you want to build, including a game console, a general entertainment system or an Office 365 dynamo.

However, each form factor is accompanied by compromises: we will cover the following ones.


If you're creating a gaming PC for the first time, an ATX card is probably your best choice, with MicroATX coming in second. The larger space obtained with an ATX makes it more forgiving and allows you to set up all the components with relative ease.

Even though ATX is great, there is no reason to stay away from the MicroATX if you are a beginner and want something a little more compact. Setting everything up is a little tighter, but still feasible. If you decide to use a MicroATX, however, pay attention to the size of the case. You do not want a case that also accepts ATX if you want to build something smaller. In addition, some MicroATX enclosures are slightly wider than ATX-compatible center towers, so look closely at the case dimensions.

The Mini-ITX is the most "hard" of the three for games, because there is very little room in the case. You can create a solid gaming PC with a Mini-ITX card, but you have to take into account the flexibility of the graphics card, ventilation and cooling. There is not much room in a dedicated Mini-ITX case, especially compared to a complete ATX case.

Home Theater PC (HTPC)

A very small Intel NUC case in silver and black revealing the rear input / output ports.An Intel NUC is an excellent home theater PC. Intel

Very often, space is the primary consideration when you add another device to an already overflowing entertainment center. This is where a Mini-ITX really shines, because you get a complete living room computer in a tiny case. Of course, you can buy an ATX box that works with Mini-ITX cards. But if you want to install it on a shelf under your TV, you need something more compact.

We would be angry if we did not mention an even smaller Intel motherboard called the NUC. Intel has introduced NUC kits as a way to build tiny, yet capable computers. NUC motherboards are typically four inches by four, and the housings are very tight.

Usually, you buy NUCs in a kit that includes motherboard, processor, discrete graphics (which vary by kit) and RAM. It's up to you to add storage or devices; However, current NUCs do not accept full-size graphics cards. Thus, a NUC only works if you want a PC primarily for video streaming, home media library management or casual gaming.


PC family

Dealer choice! Family computers should be able to do this, but they do not have to be great interpreters because you use them primarily for streaming video, email, social media, and web games. Examine what you can get for sale and let him dictate how construction works. If space is a problem, take a look at the MicroATX or Mini-ITX.

L & # 39; s future

A futuristic white and clear PC with a small touch screen.The Asus Prime Utopia concept. Asus

As mentioned before, ATX is an old specification. In the world of technology, it is difficult to dislodge anything with this kind of resistance (see Windows XP). Intel tried to introduce a replacement for ATX called BTX in 2004, but it never made it's way.

Computer manufacturers are still experimenting with alternatives to ATX. At Computex 2019, Asus unveiled a high-end motherboard concept called Prime Utopia. It looked very cool and completely different from everything we have now. This is a two-way motherboard, with voltage regulator modules (VRM) on the back, where they can be more easily cooled, which improves performance. The graphics card is also in the back, in a room reserved for better cooling, and is mounted vertically for more stability.

Asus has made the ports of I / O modular. This means that you can only insert what you need, such as additional Ethernet ports or many USB ports, and you can also empty the microphone and headphone ports. And since the graphics card at the rear releases a lot of space and reduces heat problems, the Utopia also has four m.2 slots.

Concepts such as Prime Utopia are excellent, but it is unlikely that we would see a change of ATX in the near future. ATX and its related standards have served the computer enthusiast community well for decades. Everyone is used to it and the best practices for building, maintaining and cooling these computers are well established.

These three types of motherboards are quite capable of doing any job. Your ultimate choice depends on the amount of space you have, your level of experience in building PCs and your desire for scalability for the future.

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