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The most reliable way to tell whether a motherboard is ATX or micro-ATX is to find its exact model number and check the manufacturer’s specifications or manual. If you cannot identify the model, measure the board: standard ATX is about 305 × 244 mm, while micro-ATX is about 244 × 244 mm. Use slot count and appearance only as supporting clues, especially before choosing a replacement case.
Find the motherboard model first
Look for the model name or number printed directly on the motherboard, often between expansion slots or near the memory sockets. If the board is difficult to access, check the computer’s product information or the manufacturer’s parts list for the system. For a prebuilt PC, identify the computer’s exact model as well: some manufacturers use proprietary board layouts rather than standard desktop dimensions.
Search the motherboard maker’s product page or manual for the model’s stated form factor and dimensions. That documentation is more reliable than judging the board by its shape or number of slots. Intel notes that desktop motherboard dimensions are standardized, but specialized prebuilt desktops may vary.
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If you cannot confirm the model, measure the board’s longest edge and then the perpendicular edge. Compare the measurements with these common published sizes:
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- Advanced Thermal Armor: Enlarged VRM heatsinks layered with 5 W/mk thermal pads for better heat dissipation. Pre-Installed I/O Armor for quicker PC DIY assembly.
- Boost Your Memory Performance: Compatible with DDR4 memory and supports 4 x DIMMs with AMD EXPO Memory Module Support.
- Comprehensive Connectivity: WIFI 6, PCIe 4.0, 2x M.2 Slots, 1GbE LAN, USB 3.2 Gen 2, USB 3.2 Gen 1 Type-C
| Form factor | Common dimensions | What the shape suggests |
|---|---|---|
| ATX | 305 × 244 mm (12 × 9.6 in) | Rectangular; longer than micro-ATX |
| Micro-ATX | 244 × 244 mm (9.6 × 9.6 in) | Approximately square and shorter |
Intel’s Gaming Motherboard Buying Guide and MSI’s ATX and micro-ATX comparison give matching standard dimensions. A 300 mm metric ruler can help with a rough check, but careful measurement and model documentation matter more than buying a measuring tool.
Dimensions are a strong clue, not a guarantee. A board that is shorter than standard ATX is not automatically micro-ATX; manufacturer-specific and proprietary OEM designs can differ. If the measurements do not match either standard closely, use the board or computer manufacturer’s documentation rather than forcing it into one category.
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- FROZR GUARD - Premium cooling features such as 7W/mK MOSFET thermal pads, extra choke thermal pads and an Extended Heatsink; Includes chipset heatsink, EZ M.2 Shield Frozr II, and a Combo-fan (for pump & system) header (3A)
- DDR5 MEMORY, PCIe 5.0 x16 SLOT - 4 x DDR5 DIMM SMT slots enable extreme memory overclocking speeds (1DPC 1R, 8400+ MT/s); 1 x PCIe 5.0 x16 SMT slot (128GB/s) with Steel Armor II supports cutting-edge graphics cards
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- CONNECTIVITY - Network hardware includes a full-speed Wi-Fi 7 module with Bluetooth 5.4 & 5Gbps LAN; Rear ports include USB 20G Type-C and 7.1 USB High Performance Audio with Audio Boost 5 (supports S/PDIF output)
Use expansion slots as a secondary clue
ATX boards commonly have more expansion positions than micro-ATX boards, but slot count is not a definitive identifier. Intel describes standard consumer ATX boards as usually having seven expansion slots; its micro-ATX description mentions two full-size x16 expansion slots. These are typical patterns, not requirements for every model. Memory-slot counts are also not a reliable distinction: both form factors can have four DIMM slots.
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Rank #3
- AM4 socket: Ready for AMD Ryzen 3000 and 5000 series, plus 5000 and 4000 G-series desktop processors.Bluetooth v5.2
- Best gaming connectivity: PCIe 4.0-ready, dual M.2 slots, USB 3.2 Gen 2 Type-C, plus HDMI 2.1 and DisplayPort 1.2 output
- Smooth networking: On-board WiFi 6E (802.11ax) and Intel 2.5 Gb Ethernet with ASUS LANGuard
- Robust power solution: 12+2 teamed power stages with ProCool power connector, high-quality alloy chokes and durable capacitors
- Renowned software: Bundled 60 days AIDA64 Extreme subscription and intuitive UEFI BIOS dashboard
Check case compatibility before buying
A smaller motherboard may fit a case that supports a larger form factor, but compatibility depends on the particular board and case. Check the case manufacturer’s supported-form-factor list and confirm that the case accommodates the board’s actual dimensions and mounting points. A case described as a “mid-tower” or “mini-tower” is not, by that label alone, proof that your board will fit.
Intel explains that a motherboard’s form factor affects the case size and expansion slots available in its motherboard buying guide. Before purchasing, compare the board’s manufacturer-stated form factor and dimensions with the case maker’s compatibility information. If the PC is a prebuilt system or the board has nonstandard dimensions, rely on the exact system and case documentation.
Quick Recap
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- Cutting-Edge Thermal Design: 6mm Heatpipe, Fully Covered MOSFET Heatsinks, M.2 Thermal Guard, PCIe Ultra Durable Armor
- Next Gen Connectivity: PCIe 5.0, PCIe 5.0 NVMe x4 M.2, Front and rear USB-C
Rank #4
- AMD Socket AM5: Supports AMD Ryzen 9000 / Ryzen 8000 / Ryzen 7000 Series Processors
- DDR5 Compatible: 4*DIMMs
- Power Design: 14+2+2
- Thermals: VRM and M.2 Thermal Guard
- Connectivity: PCIe 5.0, 3x M.2 Slots, USB-C, Sensor Panel Link
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
