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Rectangular ATX motherboard in matte black with silver heatsinks and a rear I/O shield

MSI

MSI MEG B550 UNIFY AM4 AMD motherboard

SKU CH-KF89-NJC32

ATX board with AM4 socket, four DDR4 slots up to 128 GB, one PCIe 4.0 x16 slot, six SATA ports and four M.2 slots

  • CPU Socket TypeAM4
  • CPU TypeSupports AMD Ryzen 5000 & 3000 Series desktop processors (no
  • ChipsetAMD B550
  • Number of Memory Slots4x288pin (DDR4)
  • Memory StandardAMD Ryzen 4000 G-Series processors support DDR4 5100+ (Max.
  • Maximum Memory Supported128GB
  • Supports Ryzen 5000 and 3000 series processors via AM4 socket
  • Four DDR4 slots deliver up to 128 GB dual-channel memory capacity
  • PCIe 4.0 x16 slot enables full-bandwidth graphics and storage
  • Four M.2 slots accept 2280 and 22110 devices with SATA and PCIe 3.0 or 4.0 support
  • Realtek ALC1220P codec provides 7.1-channel audio with S/PDIF output

AM4 B550 motherboard for Ryzen 5000 and 3000 series

This ATX motherboard uses the AMD B550 chipset and AM4 socket. It supports Ryzen 5000 and 3000 series desktop processors, plus Ryzen 4000 G-Series CPUs. The board does not work with Ryzen 5 3400G or Ryzen 3 3200G.

Four DDR4 slots and four M.2 slots suit

Builders needing up to 128 GB of dual-channel DDR4 and multiple M.2 drives will fit here. The second PCIe x16 slot runs at x4 speed and disables when an M.2 SSD occupies M2_4. Both x1 slots disable when M2_2 is used in chipset mode. Users wanting full x16 bandwidth on a second GPU should look elsewhere.

Dual-channel DDR4 up to 128 GB

Ryzen 4000 G-Series CPUs enable DDR4 speeds up to 5600 MHz via A-XMP OC MODE. The board handles 128 GB across four 288-pin slots comfortably. Memory support drops to standard JEDEC speeds with Ryzen 5000 or 3000 series chips, so maximum frequency depends on the installed processor.

Highlights

  • Supports Ryzen 5000 and 3000 series processors via AM4 socket
  • Four DDR4 slots deliver up to 128 GB dual-channel memory capacity
  • PCIe 4.0 x16 slot enables full-bandwidth graphics and storage
  • Four M.2 slots accept 2280 and 22110 devices with SATA and PCIe 3.0 or 4.0 support
  • Realtek ALC1220P codec provides 7.1-channel audio with S/PDIF output

Specifications

BrandMSI
ModelMEG B550 UNIFY
CPU Socket TypeAM4
CPU TypeSupports AMD Ryzen 5000 & 3000 Series desktop processors (not compatible with AMD Ryzen 5 3400G & Ryzen 3 3200G) and AMD Ryzen 4000 G-Series desktop processors
ChipsetAMD B550
Number of Memory Slots4x288pin (DDR4)
Memory StandardAMD Ryzen 4000 G-Series processors support DDR4 5100+ (Max. 5600)/ 5000/ 4866/ 4800/ 4733/ 4600/ 4533/ 4400/ 4266/ 4133/ 4000/ 3866/ 3733/ 3600/ 3466/ 3200/ 3066/ 3000/ 2933/ 2800/ 2667 MHz by A-XMP OC MODE
3rd Gen AMD Ryzen processors supports DDR4 5100+/ 5000/ 4866/ 4800/ 4733/ 4600/ 4533/ 4400/ 4266/ 4133/ 4000/ 3866/ 3733/ 3600/ 3466/ 3200/ 3066/ 3000/ 2933/ 2800/ 2667 MHz by A-XMP OC MODE
Supports DDR4 3200/ 3066/ 3000/ 2933/ 2800/ 2667/ 2400/ 2133/ 1866 MHz by JEDEC
AMD Ryzen 4000 G-Series processors:
1DPC 1R max speed 5100 MHz (QVL), Max. 5600 MHz
1DPC 2R max speed 4266 MHz
2D
Maximum Memory Supported128GB
Channel SupportedDual Channel
PCI Express 4.0 x161 x PCIe 4.0/3.0 x16 slot (PCI_E1) *
* The supported specification depends on installed processor.
PCI Express 3.0 x161 x PCIe 3.0 x16 slot (PCI_E4), supports x4 speed
* The PCI_E4 slot will be unavailable, when installing M.2 SSD into M2_4.
PCI Express x161 x PCI Express x16
PCI Express x12 x PCIe 3.0 x1 slots (PCI_E2 & PCI_E3)
* The both PCIe x1 slots will be unavailable after you install the M.2 SSD into M2_2 slot in Chipset support mode (default mode).
Serial ATA (SATA)6 x SATA 6Gb/s ports 1 2
1. The SATA5 port will be unavailable when installing M.2 SATA SSD into M2_3.
2. The SATA5 and SATA6 ports will be unavailable when installing M.2 PCIe SSD into M2_3.
M.24 x M.2 slots (Key M)
M2_1 slot (from CPU):
Supports PCIe 4.0/3.0 x4*
Supports SATA 6Gb/s
Supports 2280/22110 storage devices
M2_2 slot:
Chipset support mode (default, from Chipset ) - supports PCIe 3.0 x2
CPU support mode (From CPU) - supports PCIe 4.0/3.0 x4 *
Supports 2280 storage devices
M2_3 slot:
Chipset support mode (default, from Chipset ) - supports PCIe 3.0 x2
CPU support mode (From CPU) - supports PCIe 4.0/3.0 x4 *
Supports SATA 6Gb/s
Supports 2280/22110 storage devices
M2_4 slot:
Supports PCIe 3.0 x4
Supports 2280 storage devices
* M.2 specifications may vary depending on
SATA RAID0/1/10
Onboard Video ChipsetSupported only by CPU with integrated graphic:
1 x HDMI 2.1 port, supporting a maximum resolution of 4096x2160 @120 Hz 1 2
Maximum shared memory of 16GB
1. Available for the processor with integrated graphics.
2. Graphics specifications may vary depending on the CPU installed.
Audio ChipsetRealtek ALC1220P Codec
Audio Channels7.1-Channel High Definition Audio
Supports S/PDIF output
LAN ChipsetRealtek RTL8125B
Max LAN Speed2.5Gbps
Wireless LANIntel Wi-Fi 6 AX200
The Wireless module is pre-installed in the M.2 (Key-E) slot
Supports MU-MIMO TX/RX, 2.4GHz/5GHz (160MHz) up to 2.4Gbps
Supports 802.11 a/ b/ g/ n/ ac/ ax
BluetoothSupports Bluetooth 5.1
USB 3.04 x USB 3.0
Onboard USB1 x USB 3.2 Gen 2 10Gbps Type-C port
1 x USB 3.2 Gen 1 5Gbps connector (supports additional 2 USB 3.2 Gen 1 5Gbps ports)
2 x USB 2.0 connectors (supports additional 4 USB 2.0 ports)
Other Connectors1 x 4-pin CPU fan connector
1 x 4-pin water-pump fan connector
6 x 4-pin system fan connectors
1 x Front panel audio connector
2 x System panel connectors
1 x Chassis Intrusion connector
1 x 4-pin RGB LED connectors
2 x 3-pin RAINBOW LED connectors
1 x 3-pin CORSAIR LED connector
1 x TPM module connector
1 x Clear CMOS jumper
1 x Power button
1 x Reset button
Form FactorATX
LED LightingRGB
Dimensions (W x L)12.0" x 9.6"
Power Pin1 x 24-pin ATX main power connector
2 x 8-pin ATX 12V power connector
1 x 6-pin PCIE power connector
Windows 11Supported
FeaturesSupports AMD Ryzen 5000 & 3000 Series desktop processors (not compatible with AMD Ryzen 5 3400G & Ryzen 3 3200G) and AMD Ryzen 4000 G-Series desktop processors.
Supports DDR4 Memory, Dual Channel 5100(OC) MHz+.
Quadruple M.2 Connectors: Maximum onboard 4 x M.2 slots, support the latest Gen 4 solution with up to 64GB/s bandwidth for maximum transfer speed.
Extreme Power Design: Direct 14+2 phases with 90A Power Stage and dual CPU power connectors to unleash your true power.
Premium Thermal Solution: Aluminum Cover with additional choke thermal pad rated for 7W/mk and PCB with 2oz thic

Questions about this item

Does the MEG B550 UNIFY need a specific CPU cooler bracket for the AM4 socket?

The board uses the standard AM4 mounting holes, so any cooler labelled for AM4 fits without an extra bracket.

If I keep my PCIe 3.0 graphics card, will it run at full speed in the top slot?

The primary PCI_E1 slot supports PCIe 4.0 and 3.0 x16, so a PCIe 3.0 card operates at its native x16 speed.

How can I confirm the M.2 drive in the M2_1 slot is running at PCIe 4.0 x4?

Install a Ryzen 5000 or 3000 series CPU, then check the BIOS or OS device manager — it should report a PCIe 4.0 x4 link for M2_1.

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