Motherboard Sizes in 2025: How to Choose Between ATX, MicroATX, Mini-ITX, and More

When you start building a PC, one of the first decisions you’ll need to make is choosing the right motherboard size. Over the years, motherboard form factors have evolved, offering a wide range of options to suit different needs, from powerful gaming PCs to compact home theaters. In this article, we’ll cover the main options available today so you can make an informed choice.

Why does motherboard size matter?

The size of the motherboard determines its compatibility with the case and components. For example, a large EATX board will not fit into a compact microATX case. And although a small Mini-ITX can be installed in a large case, this will lead to the loss of the main advantage of the compact form factor, limiting expansion options and complicating the PC assembly process.

To make it easier to find compatible components, manufacturers adhere to industry standards. For example, ATX motherboards have standardized dimensions and mounting holes, which makes it easier to install in ATX cases.

Main dimensions of motherboards

Here's a quick overview of the most common motherboard form factors in 2025:

• ATX – the most popular standard, providing maximum compatibility and wide expansion possibilities.
• microATX — a more compact ATX option that offers a good balance between size and functionality.
• Mini-ITX – an ideal choice for ultra-compact builds such as media centers or minimalist gaming systems.
• EATX – a larger version of ATX, which offers advanced features for enthusiasts and professionals.

There are other form factors, but these are the most common among PC builders.

ATX: The standard choice

The ATX form factor (12 x 9,6 inches) remains the optimal choice for most users. It supports multiple expansion slots, typically has four DIMM slots for RAM, and offers a wide selection of ports.

One of the reasons for the popularity of ATX is the large size of modern graphics cards. Since they often take up two or more PCIe slots, an ATX case provides enough space to install them. Additionally, there are many models of ATX cases and motherboards available on the market, making the choice easier. This can be a good enough reason to choose ATX over other motherboard options, as it almost 100% guarantees that you will find the desired design or the exact set of features for your motherboard.

microATX: compact but functional

MicroATX (9,6 x 9,6 inches) motherboards are a great choice for those who don’t need a lot of expansion slots. They typically have up to four PCIe and DIMM slots, which is enough for most users.

The main advantage of microATX is the ability to use more compact cases. For example, the ASUS Prime AP201 case is compatible with graphics cards up to 338 mm long and standard ATX power supplies, while maintaining compact dimensions.

Mini-ITX: The Best Choice for Small Cases

If you're looking for a small form factor PC, you should consider a Mini-ITX (6,7 x 6,7 inches). These boards typically have one PCIe slot and two DIMM slots, but they can easily support powerful processors and graphics cards.

The compactness of Mini-ITX requires careful planning of the build, especially when it comes to cooling. NVIDIA's GeForce SFF-Ready program simplifies the process of building a space-saving PC by labeling cases and graphics cards SFF-Ready. When you choose a case and graphics card that are both SFF-Ready, you can be sure that they are suitable for building an ultra-compact PC. For example, the compact yet powerful ASUS Prime graphics cards deliver the performance you need in a relatively small package.

Even smaller options

If even Mini-ITX seems too big, consider ultra-compact solutions like the ASUS NUC mini PC. These systems are typically about 4,6 inches on each side and are available as complete PCs, barebones kits, or individual boards. They are typically targeted at small businesses, retail outlets, and healthcare facilities, but are also suitable for creating a home media center or workstation.

EATX: maximum possibilities

EATX motherboards are wider than ATX, allowing for more expansion slots, DIMMs, and additional power connectors. They are often used for premium gaming systems and workstations that require maximum performance.

Professional options: CEB and EEB

For servers and workstations, specialized CEB and EEB boards are used, which support multi-core AMD Ryzen Threadripper and Intel Xeon processors, as well as multiple video cards and huge amounts of RAM.

How to choose the right size?

In 2025, choosing a motherboard depends on your needs.

• For general purpose PC - ATX
• For a compact yet productive PC — microATX
• For ultra-compact assembly – Mini-ITX
• For enthusiasts and professionals – EATX
• For servers and workstations - CEB or EEB

If you're building an AMD-based PC, consider the enthusiast-grade X870E/X870 or mainstream B850 motherboards. For Intel, consider the overclockable Z890 or B860 models for the best value.