Motherboard Sizes Explained: ATX, Micro-ATX, Mini-ITX & More

Before you buy a case or start building, make sure your parts will actually fit together. Here’s what you need to know:

ATX (Advanced Technology eXtended)

• Standard size for most “full-size” desktop PCs.

• Lots of space for multiple GPUs, extra RAM, more drives, and expansion cards.

• Great for power users, upgraders, or anyone building a performance machine.

• Needs a case that supports ATX (most mid/full towers).

Micro-ATX (mATX)

• Smaller than ATX, but still has 4 RAM slots and a couple of GPU/expansion slots.

• Easier to fit in compact cases.

• Good balance of features vs. size.

Mini-ITX

• Tiny boards, big savings on space.

• Usually only one slot for a GPU, two for RAM, and limited expansion.

• Perfect for small form-factor builds, living rooms, or travel rigs.

• Downside: Not much room for upgrades or multiple drives/GPUs.

Other Form Factors (For the Curious)

• E-ATX (Extended ATX):

  • Even bigger than ATX. Serious workstation and enthusiast boards.

• Nano-ITX, Pico-ITX:

  • Smaller still, usually for ultra-compact or specialty devices.

Case Compatibility

• Always check what sizes your case supports (it’s in the product specs).

• Some mid-tower cases fit ATX, mATX, and Mini-ITX—others are built for just one.

• Want more drives, GPUs, or cooling?

  • Go bigger! Smaller cases are stylish, but they limit expansion, airflow, and sometimes even performance.

Echo’s Tips

• If you want future upgrades, go ATX or larger.

• For a tiny, minimalist build, Mini-ITX is cool—but plan your parts carefully.

• Don’t forget: the smaller the case, the trickier the build (tighter cables, less airflow).

Bottom Line: Motherboard size = case size = your upgrade path. Plan your build before you shop—and double-check those specs so you don’t get stuck!