Does Motherboard Size Matter?

You’ve studied all of the benchmarks to the point where you could recite them in your sleep. You’ve logged hours on YouTube watching all of the reviews. You visited dozens of forums. You even called your weird uncle who’s an IT manager at some company you’ve never heard of. You finally made a decision and are just about to pull the shrink wrap off the box of your shiny new CPU.

Then it hits you: What motherboard should I get?

The motherboard is the main board to which all of the major electronic components in a computer attach, providing them with power and allowing them to communicate with each other. The CPU, RAM, graphics, sound, networking, and sometimes flash storage are connected directly to the motherboard. The motherboard also controls hard drives, solid state drives (SSDs), fans, and USB peripherals. So it’s easy to see how important it is to find just the right motherboard for your particular needs.

Why Motherboard Size Matters

Choosing the right PC motherboard to go with your awesome new CPU can be a daunting challenge. There are tools like PCPartPicker, Intel’s Desktop Compatibility Tool, and AMD’s Motherboard Recommendation website that can tell you which ones are compatible with your CPU. What they won’t tell you, however, is which is best for your particular needs. Fortunately most popular motherboards adhere to one of several different industry standards which are primarily based on features that ultimately determine physical size. These standards apply regardless of whether you are using a CPU from Intel or AMD, but you will need to check that the motherboard you choose is compatible with and takes full advantage of the CPU that you’ve chosen. So if you haven’t already decided on what size computer you want to build, now is the time!

Motherboard size does matter and depends on the type of PC you are building.


The most popular standard for PC motherboards is ATX, which stands for Advanced Technology Extended. ATX motherboards are considered to be full-size with up to seven PCI/PCI Express (PCIe) expansion slots. Expansion slots are needed for things like graphics cards, sound cards, NVMe PCIe Solid State Drives (SSDs), and various peripherals. They also provide up to eight slots for RAM. These boards are generally used in ATX mid-tower cases like the Noctis 450.

ATX motherboards offer decent space for components and cooling while still fitting nicely on top of a desk. This can be limiting, however, when you need more graphics horsepower, cooling, or storage for a serious gaming rig or CAD workstation. Fortunately, full-tower cases like the Switch 810 also support ATX motherboards. This gives you a lot more room to add multiple graphics cards, commonly referred to as SLI or Crossfire depending on the manufacturer, and cooling equipment, like fans, pumps, and radiators.

Motherboard sizes vary significantly.


If you need a computer that is really small then you should look to Mini-ITX. These boards are primarily used in small form factor (SFF) computer systems where the entire computer must fit in a cabinet or on a bookshelf or otherwise be very portable. Typical uses include home theater PCs (HTPCs) where low power consumption means less noise from cooling fans and LAN gaming where you need something that is easy to carry around. Many new CPUs include integrated graphics eliminating the need for a dedicated graphics card if you aren’t after high resolution and/or high frame rates. This is good, because the Mini-ITX standard allows for just one PCI expansion port. To take full advantage of the smaller form factor you may need to find something other than a standard ATX power supply as they are generally too large for small Mini-ITX cases. Check with the case manufacturer to see what they support.


On the other hand, if space is not your concern, but performance and reliability are then eATX is for you. The e stands for extended making this an Extended Advanced Technology Extended motherboard. Boy that’s a mouthful. Generally these are used for enterprise-class high-performance workstations and servers. While it’s the same height as an ATX motherboard, it is 86 mm (3.39 inches) wider. This additional space is generally used for a second CPU, but single CPU boards are also available. They also have eight memory slots and up to seven PCI expansion slots, but using an older 64-bit PCI standard called PCI-X (PCI Extended). Wow, these computer standards people really like adding Extended to things, don’t they? While you can typically use the same types of CPUs on an eATX that you would use on an ATX motherboard, you can’t always run a PCI card in a PCI-X slot without seriously degrading system performance. PCIe cards will never work in a PCI-X slot. You’ve been warned! Check with the motherboard and card manufacturer to ensure compatibility before you buy. Again the I/O panel is the same between ATX and eATX. Most users building with an eATX motherboard will opt for a full-tower case for the added room that it affords for drive storage. However, many mid-tower cases can be modified to accept eATX motherboards, though it will likely be a tight fit and cable management may be difficult.

More Options

There are other standards for PC motherboards out there that are even larger (XL-ATX) and smaller (Pico-ITX and Nano-ITX), but those are much less common than the ones described above. For most applications, ATX will provide the performance and features that you need. If you are in the market for a new motherboard, more likely than not it will be one of the ones mentioned above. You will find a wide selection at most computer component stores giving you plenty of options to suit your needs and budget. You will also have more choices when it comes to cases.

What do you think? Are there certain features that you look for that make you want to use a less common size? Do you prefer larger boards with more features and performance or smaller ones that are quiet and efficient? Let us know in the comments below.