MSI
MSI B550M-A PRO AMD B550 AM4 DDR4 64GB Micro ATX Motherboard
Micro-ATX board for Socket AM4 Ryzen CPUs with dual-channel DDR4 up to 64 GB, PCIe 4.0 x16, four SATA III ports, 7.1 audio and gigabit LAN
- CPU Socket TypeSocket AM4
- CPU TypeSupport 3rd Gen AMD Ryzen Desktop Processors and AMD Ryzen40
- ChipsetAMD B550
- Memory StandardSupport dual-channel DDR4 1866/2133/2400/2667/2800/2933/3000
- Maximum Memory Supported64GB
- PCI Slots1x PCIe 3.0 x1 slot 1x PCIe 4.0/3.0 x16 slot
- Supports 3rd Gen Ryzen and Ryzen 4000 G-Series CPUs via Socket AM4
- Dual-channel DDR4 up to 4600 MHz with 64 GB maximum capacity
- PCIe 4.0 x16 slot plus PCIe 3.0 x1 slot for expansion cards
- Realtek ALC892/897 codec delivers 7.1-channel high-definition audio
- Realtek RTL8111H Gigabit LAN plus USB 3.2 Gen 1 and USB 2.0 connectivity
AM4 socket motherboard for Ryzen CPUs
The MSI B550M-A PRO is a micro-ATX board built around the AMD B550 chipset. It accepts Socket AM4 processors including 3rd Gen Ryzen desktop chips and Ryzen 4000 G-Series APUs. Dual-channel DDR4 memory runs at speeds from 1866 up to 4600+ MHz with a 64 GB capacity ceiling.
Builders needing one full-size GPU slot
This board suits compact systems that rely on a single PCIe 4.0 x16 graphics card and up to four SATA III drives plus one M.2 device. It lacks a second x16 slot and provides only one PCIe 3.0 x1 lane, so multi-GPU arrays or heavy add-in card counts are not practical.
Single PCIe 4.0 x16 slot for graphics
The only full-length expansion lane is a PCIe 4.0/3.0 x16 slot wired for a graphics card. No second x16 or x8 electrical lane exists, so the build cannot accommodate dual discrete GPUs or a GPU plus a high-bandwidth capture card.
Highlights
- Supports 3rd Gen Ryzen and Ryzen 4000 G-Series CPUs via Socket AM4
- Dual-channel DDR4 up to 4600 MHz with 64 GB maximum capacity
- PCIe 4.0 x16 slot plus PCIe 3.0 x1 slot for expansion cards
- Realtek ALC892/897 codec delivers 7.1-channel high-definition audio
- Realtek RTL8111H Gigabit LAN plus USB 3.2 Gen 1 and USB 2.0 connectivity
Specifications
| Brand | MSI |
|---|---|
| Series | MSI B550M-A PRO |
| Model | MSI B550M-A PRO |
| CPU Socket Type | Socket AM4 |
| CPU Type | Support 3rd Gen AMD Ryzen Desktop Processors and AMD Ryzen4000 G-Series Desktop Processors |
| Chipset | AMD B550 |
| Memory Standard | Support dual-channel DDR4 1866/2133/2400/2667/2800/2933/3000/3066/3200/3466/3600/3733/3866/4000/4133/4266/4533/4600 + MHz memory |
| Maximum Memory Supported | 64GB |
| PCI Slots | 1x PCIe 3.0 x1 slot 1x PCIe 4.0/3.0 x16 slot |
| SATA RAID | 1XM.2 interface, 4xSATA III interface |
| Audio Chipset | Realtek ALC892/ALC897 Codec 7.1-Channel High Definition Audio |
| LAN Chipset | 1x Realtek RTL8111H Gigabit LAN controller |
| Onboard USB | AMD B550 Chipset 2x USB 3.2 Gen 1 5Gbps ports are available through the internal USB 3.2 Gen 1 5Gbps connector 6x USB 2.0 ports (2 Type-A ports on the back panel, 4 ports through the internal USB 2.0 connectors) AMD Processor 4x USB 3.2 Gen 1 5Gbps Type-A ports on the back panel |
Questions about this item
Will the CMOS battery need replacing on the MSI B550M-A PRO?
The board ships with a CMOS battery included; it typically lasts several years before a replacement is required.
What limits sustained performance on the MSI B550M-A PRO?
The VRM heatsink area is the first constraint during long heavy loads on Socket AM4 Ryzen CPUs.
How loud and hot does the MSI B550M-A PRO get under all-day use?
Passive VRM cooling and the Realtek RTL8111H LAN run silently; chassis fans determine actual noise and temperature.
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