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Dark green Micro-ATX board with extended silver heatsinks and pre-fitted I/O shield

MSI

MSI MAG B550M MORTAR AMD motherboard AM4 DDR4 PCIe 4.0 SATA 6Gb/s M.2 Micro-ATX

SKU CH-52K0-64XFP

Micro-ATX board for Ryzen CPUs with DDR4 memory up to 128 GB at 4400 MHz, PCIe 4.0 and SATA 6Gb/s M.2 slots, extended heatsink and pre-installed I/O shield

  • Form factorMicro-ATX
  • Supports up to 128 GB DDR4 memory at 4400 MHz
  • Extended heatsink with 7W/mk choke thermal pad and 2oz copper PCB
  • PCIe 4.0 ready for high-speed storage and graphics
  • Pre-installed I/O shield simplifies build and protects against static
  • Micro-ATX form factor fits compact cases without sacrificing features

Compact foundation

The MSI MAG B550M MORTAR is a Micro-ATX motherboard built for AMD Ryzen processors on the AM4 socket. It delivers PCIe 4.0 connectivity and dual-channel DDR4 support in a space-efficient layout. A pre-installed I/O shield simplifies assembly, while the extended heatsink and thickened copper PCB handle thermal demands. The board targets builders who want current-generation features without a full-size ATX footprint.

Who benefits, who looks elsewhere

This board suits gamers and creators upgrading to 3rd Gen Ryzen or planning a future Ryzen CPU with a BIOS update. It also fits compact cases where a Micro-ATX form factor is required. Builders who need more than four memory slots, additional full-length PCIe slots, or a larger ATX feature set should consider a different form factor. Users staying on older AM4 processors without BIOS update support will also need another option.

Build integration

The board accepts up to 128 GB of DDR4 memory at speeds reaching 4400 MHz, freeing you to populate all four slots for high-capacity workloads. PCIe 4.0 lanes serve the primary graphics slot and a fast M.2 connection, while SATA 6Gb/s ports remain available for additional drives. The premium thermal solution covers the VRM area, reducing the need for aggressive case airflow directly over the power phase. Ensure your chassis accommodates the Micro-ATX mounting pattern and rear I/O cutout.

How it compares

Measured against everything we stock in Motherboards for AMD CPUs, at today’s prices. Recalculated every night.

Price $90.99
Cheaper than about 79% of the 1,906 comparable items (median $224.49).

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Specifications

Product
Brand nameMSI
Model nameMAG B550M MORTAR
Size & build
Form factorMicro-ATX

Questions about this item

Do I need a 3rd Gen AMD Ryzen processor to use the MSI MAG B550M MORTAR?

The board supports 3rd Gen AMD Ryzen processors out of the box and future AMD Ryzen processors with a BIOS update.

Will my existing DDR4 memory modules work with the 4400 MHz capability of this board?

The motherboard supports dual channel DDR4 memory up to 128 GB at 4400 MHz, so compatible DDR4 modules will function at their rated speeds.

How can I verify the extended heatsink and choke thermal pad are cooling effectively after assembly?

Monitor VRM and choke temperatures under load using hardware monitoring software; the premium thermal solution with 7W/mk pad and 2oz copper PCB is designed to maintain lower operating temperatures.

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