ATX vs Micro ATX vs Mini ITX Motherboards
ATX, Micro ATX and Mini ITX are standard board sizes that set which cases fit and how many slots you get; ATX is the most common size we list.
By Paul SyversonFounder.
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The short answer
A form factor is a standard size and mounting layout for a motherboard. It decides which PC cases the board fits and how much room it has for expansion cards and memory slots. The three common sizes for desktop builds are ATX, Micro ATX (also written mATX) and Mini ITX.
Pick the size that matches your case and the number of slots you need. A larger board gives more room for parts; a smaller one lets you build a smaller PC.
The sizes side by side
These are the maximum board sizes and slot counts listed in the Wikipedia overview of motherboard form factors. The same overview notes that Intel introduced ATX in 1995.
| Form factor | Maximum size | Maximum expansion slots |
|---|---|---|
| E-ATX | 305 x 330 mm (12 x 13 in) | 7 |
| ATX | 305 x 244 mm (12 x 9.6 in) | 7 |
| Micro ATX | 244 x 244 mm (9.6 x 9.6 in) | 4 |
| Mini ITX | 170 x 170 mm (6.7 x 6.7 in) | 1 |
E-ATX (extended ATX) has no single standard, so its exact size can differ by maker. Check that your case lists E-ATX support before you buy one.
Form factors on Wiki Shopping
How many of the 621 motherboards on Wiki Shopping state each form factor in their listing, from our page data on October 25, 2026. Each size links to its filter page.
What is a motherboard chipset?
The chipset is the set of chips on the board that connects the processor to the rest of the PC: storage, USB ports, extra PCIe lanes and more. It also sets which features the board supports. Chipset names are tied to a processor family, such as AMD B650 or Intel Z790, so the chipset and the socket have to match the processor you plan to use.
How to choose a motherboard
- Start with the processor. The board's socket must fit it, for example AM5 or LGA1700.
- Match the memory type. A board takes either DDR4 or DDR5 memory, not both. On Wiki Shopping, 200 boards list DDR4 and 191 list DDR5 on October 25, 2026.
- Pick the size that fits your case. Cases list the form factors they accept. The Wikipedia overview notes that Micro ATX boards fit most ATX cases, but check the case's own specification.
- Count the slots and ports you need. More expansion cards, M.2 drives or memory sticks point to a larger board. Filters for M.2 slots and Wi-Fi 7 help narrow the list.
How we count
Each motherboard on Wiki Shopping has its form factor and memory type read from the store listing. A board has at most one form factor; boards whose listing gives none are counted as "Not stated". The counts change as listings are added or removed.
Shop by spec
Motherboards
AM5, ATX, DDR5, 3 M.2 slots
- AM5 Socket: Ready for AMD Ryzen Desktop 9000, 8000, and 7000 Series Processors
- BIOS Update maybe required when used with AMD Ryzen Desktop 9000 and 8000 Series CPU Processors
- Robust Power Solution: 12 plus 2 power stages with 8 plus 4 pin ProCool power connectors, high-quality alloy chokes, and durable capacitors to support multi-core processors
- Optimized Thermal Design: Massive VRM heatsinks with strategically cut airflow channels and high conductivity thermal pads
- Next-Gen M.2 Support: One PCIe 5.0 M.2 slot and two PCIe 4.0 M.2 slots, all with heatsinks to maximize performance
AM4, mATX, DDR4, 4 Memory slots
- AMD Socket AM4: Ready to support AMD Ryzen 5000/4000/3000 Series Processors
- Enhanced Power Solution: Digital 3+3 VRM Design and premium chokes and capacitors for steady power delivery.
- Advanced Thermal Armor: Chipset heatsinks for better heat dissipation.
- Boost Your Memory: Compatible with DDR4 and supports 4 DIMMS with Extreme Memory Profile support.
- Comprehensive Connectivity: 1x Ultra Durable PCIe 4.0 x16 slot, 1x PCIe 4.0 M.2 slot, 1x PCIe 3.0 M.2 slot, 4x USB 3.2 Gen 1 ports for hassle-free setup.
AM5, ATX, DDR5, 2 M.2 slots
- Ready for Advanced AI PC: Designed for the future of AI computing, with the power and connectivity needed for demanding AI applications
- AMD AM5 Socket: Ready for AMD Socket AM5 for AMD Ryzen 9000 & 8000 & 7000 Series Desktop Processors
- Enhanced Power Solution: 12+2+1 80A DrMOS power stages, 8-layer PCB, ProCool connectors, alloy chokes and durable capacitors for stable power delivery
- Ultrafast Connectivity: Wi-Fi 6, PCIe 5.0 x16 slot, PCIe 5.0 M.2 slot, Realtek 2.5Gb Ethernet, USB4 (40Gbps) Type-C ports, front USB 20Gbps Type-C with PD Fast Charge Support
- Comprehensive Cooling: Large VRM heatsink, Dual M.2 heatsinks, PCH heatsink, hybrid fan headers and Fan Xpert 4 with AI Cooling II
- DIY-Friendly Design: Pre-mounted I/O shield, PCIe Slot Q-Release, M.2 Q-Latch, BIOSFlashBack, Q-Dashboard, Q-LED
AM5, ATX, DDR5, 4 Memory slots
- AMD Socket AM5: Supports AMD Ryzen 9000 / Ryzen 8000 / Ryzen 7000 Series Processors
- DDR5 Compatible: 4*DIMMs with AMD EXPO Support
- Power Design: 16+2+2
- Thermals: VRM and M.2 Thermal Guard
- Connectivity: PCIe 5.0, 4x M.2 Slots, Dual USB4, Front and Rear USB-C, Sensor Panel Link