Motherboard sizes explained: which should you buy in 2025?

There are four motherboard sizes available in 2025 from major manufacturers such as Asus, Gigabyte, and MSI, among others. These are Mini-ITX, MicroATX, ATX, and E-ATX. As the naming conventions imply, the two smallest models are the mini-ITX and MicroATX options, which measure 6.7 x 6.7 inches and 9.6 x 9.6 inches, respectively.

The most common motherboard size is ATX, which measures 12 x 9.6 inches. For those that need a little extra headroom for additional components, E-ATX (Extended ATX) offers the largest amount of space with 12 x 13 inches of fiberglass available. As can be evidenced from the motherboard size chart above, there’s quite a dramatic difference in scale between Mini-ITX and MicroATX, with more of a subtle difference when comparing ATX and EATX, generally with the latter having more room on the right-hand side.

In terms of use cases, both Mini-ITX and MicroATX motherboards are favored for small form factor (SFF) work and gaming computers, such as those you may use in a low-profile office setting or a console-sized rig for living room use. As the smaller scales suggest, you can expect fewer PCIe lanes for connecting components (and a more cramped building experience) depending on the PC case you’re using. This also means limited room for some of the best CPU coolers (and more limited airflow in general), so this is something paramount to consider before you invest.

As a frame of reference, Mini-ITX is around two-thirds the size of an ATX motherboard. Historically, the former was designed for lower power consumption and efficiency when compared to the more common sizes. However, in 2025, some manufacturers have started catering to gamers and power users in this smaller size, though you (typically) will pay a premium in comparison.

Starting out with Mini-ITX motherboards, these models tend to be the more expensive way of building a small form factor (SFF machine) when compared to microATX which is (generally) considered to be a more wallet-friendly option. This is consistent in the prices that you’ll expect to pay between Mini-ITX and microATX, as reflected in today’s popular models from major manufacturers.

Socket AM5 options sell for more of a premium in the Mini-ITX form factor, as can be evidenced by the ASRock A620I Lightning Wi-Fi ($139.99), Gigabyte B850I Aorus Pro ($279.99), MSI MPG B650I Edge WiFi ($299.99) with a rough range of the budget and more premium offerings. In contrast, MicroATX equivalents are (generally) more affordable well under the $200 mark, including the ASRock B650M Pro RS ($139.99), MSI Pro B650M-A Wi-Fi ($159.99), and Gigabyte B850M Gaming X Wi-Fi 6E ($179.99).

Price and size aside, another major difference between Mini-ITX and MicroATX is the number of ports and connections available on the motherboard. Due to its cramped 6.7 x 6.7 inches available, Mini-ITX mobos usually only have a single PCIe x16 slot for the graphics card and up to two M.2 SSD ports. Depending on the manufacturer, there may only be two RAM slots instead of four, and the rear I/O could be more cut down by comparison, resulting in fewer USB ports and other connections.

MicroATX, in contrast, usually features four RAM slots, two PCIe x16 slots, up to four M.2 ports, and vastly more expansive options for its rear I/O, because you’ve got 43% more space on the motherboard. In theory, MicroATX seems to be a superior option (being cheaper and offering more); however, it’s also larger in a way that makes certain small form factor (SFF) builds harder to achieve, being less slick and compact as a result. You should make your choice depending on your use case; do you need more than dual-channel RAM, two M.2 ports, a graphics card slot, and a basic rear I/O? If so, maybe the silicon needs to be larger.

When compared to the two smaller motherboard sizes, ATX and E-ATX variants do not seem as drastically different on the surface. However, the extra space afforded by the 35% more space can be staggering, depending on the hardware you’re planning on using. While ATX motherboards traditionally feature up to four PCIe x16 ports and four RAM slots, E-ATX versions can boost things up to as high as eight PCIe x16 ports with the potential for as much as eight RAM slots (though this is unlikely in 2025 compared to historical examples).

The major drawback of E-ATX motherboards is their higher price tag when compared to ATX offerings, as well as more limited availability. While still supported for today’s current AM5 and LGA 1851 sockets, you’re going to pay a heavy premium for the extra components space on the motherboard itself. Some popular E-ATX options can elipse their ATX counterparts, as can be seen with the pricing of the ASRock X670E Taichi ($449.99) and the MSI MEG X670E ACE ($499.99). In contrast, similar ATX models are much cheaper, like the ASRock X670E Steel Legend ($259.99) and the MSI MAG X670E Tomahawk Wi-Fi ($239.99).

With that said, is the extra real estate worth potentially paying double (or more) when compared to an ATX motherboard? It will ultimately depend on the use case. The power user will get the most out of the larger board space, which can be particularly important if you’re thinking of forging a high-end creation or gaming PC featuring a custom loop in a far larger E-ATX compatible PC case, complete with bleeding-edge components. It all comes back to airflow and the space required; E-ATX will afford you as much room as possible, provided you can stomach the sticker price.

It’s commonly been debated that gamers will not see the benefit of the extra data lanes afforded by an E-ATX motherboard. Instead, those planning a server rig, a deep-learning machine, or something more granular might find the extra slots and connections of vital importance. Do you need more expansion slots? Then E-ATX may be the solution here, otherwise, ATX will satisfy the vast majority of PC users for just about any task imaginable while also being far more affordable and available.

We’ve outlined the four different motherboard sizes available in 2025, their use cases, price differences, and varying features as they stand right now. Choosing a motherboard is not as cut and dry as you would expect, and that’s why you need to visualize your rig before putting any money down. Consider the chipset of the board for starters. Will you use AMD’s AM4 or AM5 platform? Similarly, will you pay the premium investing in Intel’s latest LGA 1851 socket instead of sticking with the older (and arguably better) LGA 1700 platform that hosted Alder Lake and Raptor Lake?

All four motherboard sizes support the latest and greatest of today’s processor technology, just in different ways. Mini-ITX is pricey as you’re paying extra for the sleek form factor, whereas MicroATX provides a similarly small (but far cheaper) experience that usually does not boast the same features by comparison. ATX is the most widely used and commonly stocked motherboard, but power users may need the added versatility of an E-ATX board if they’re building a server or a dedicated workstation, even if gamers may not feel the added benefit.

Compatibility is the most important factor above all. As such, we recommend dedicated tools such as PCPartPicker when virtually pricing and sizing up a machine; you’ll get to see which motherboards support your chosen CPU, GPU, RAM, M.2 SSD, and other components efficiently, as well as get suggestions for compatible cases. Building a PC the size of a PS5 or Xbox Series X may be an exciting idea, but you may need a Mini-ITX motherboard and SFF components, which can boost the price while making things cramped to build in. The motherboard is the foundation of your whole machine, after all.