MSI B550-A PRO AM4 ATX Motherboard - PCIe 4.0, DDR4
MSI
MSI B550-A PRO AM4 ATX Motherboard - PCIe 4.0, DDR4
The MSI B550-A PRO AM4 ATX Motherboard is built for home office users and content creators who want a stable, capable platform for AMD Ryzen desktop processors without unnecessary complexity. It pairs PCIe 4.0 connectivity and dual M.2 slots with a reinforced thermal design, making it well suited to builds that run demanding workloads for extended periods. The Flash BIOS Button and EZ Debug LED reduce setup friction, so less time is spent troubleshooting and more is spent working.
Why this product
PCIe 4.0 and Gen4 M.2 support
The primary M.2 slot runs at PCIe 4.0 x4 speeds with up to 64 GB/s bandwidth, and the full-length PCIe slot also supports Gen4 for the latest graphics cards.
M.2 Shield Frozr keeps SSDs cool
A built-in M.2 heatsink covers both M.2 slots to prevent thermal throttling and keep drives running at their rated speeds during sustained workloads.
Extended heatsink with 7 W/mK thermal pad
A premium 7 W/mK thermal pad covers both MOSFETs and chokes, improving heat transfer to the heatsink and supporting non-stop operation under load.
Flash BIOS without a CPU installed
The Flash BIOS Button lets you update firmware using only a USB drive — no processor, memory or graphics card required — which simplifies builds and recovery.
USB 3.2 Gen 2 with reversible Type-C
The rear panel includes a Gen 2 Type-C port at 10 Gbps alongside a Gen 2 Type-A port, plus front-panel headers for additional USB 3.2 Gen 1 connections.
DDR4 up to 4400+ MHz with four DIMM slots
Dual-channel DDR4 support across four slots allows up to 128 GB of memory, with A-XMP overclocking profiles reaching beyond 4400 MHz for memory-intensive tasks.
- SocketAM4
- ChipsetAMD B550
- Form FactorATX
- Max Memory128 GB DDR4
- M.2 Slots2 (PCIe 4.0/3.0 x4 + PCIe 3.0 x4)
- SATA III Ports6
- USB 3.2 Gen 2 (Rear)1× Type-C, 1× Type-A
- LANRealtek Gigabit (1 GbE)
- SKUMSI-6999
- EAN4719072733667
- Compatible with AMD Ryzen 5000 Series desktop processors (AM4 socket).
- Compatible with AMD Ryzen 3000 Series desktop processors (AM4 socket).
- Compatible with AMD Ryzen 4000 G-Series desktop processors.
- Supports Windows 10 64-bit operating system.
- Integrated graphics output (DisplayPort and HDMI 2.1) requires a Ryzen processor with integrated graphics; discrete GPU builds do not use these ports.
- Not compatible with AMD Ryzen 5 3400G or Ryzen 3 3200G.
Best for
- AMD Ryzen platform builders who want a stable B550 board with PCIe 4.0 support for the latest CPUs and NVMe SSDs.
- Home office and productivity users who need reliable, long-running operation backed by extended heatsink design and premium thermal pads.
- Multi-GPU configurations using 2-Way AMD CrossFire for users who want to pair two graphics cards.
- High-capacity memory builds — four DIMM slots support up to 128 GB of DDR4, which suits content creation and virtualisation workloads.
- DIY builders who value easy setup, thanks to the Flash BIOS Button and EZ Debug LED that reduce the time needed for initial configuration and fault-finding.
Trade-offs
- Intel platform builds — this board uses an AM4 socket and AMD B550 chipset, so no Intel processor will fit.
- Builders needing integrated Wi-Fi — there is no onboard wireless; a separate Wi-Fi adapter would be required.
- Users requiring multi-gigabit LAN — the onboard controller is a Realtek Gigabit (1 GbE) port; higher-speed wired networking needs an add-in card.
- AMD Ryzen 5 3400G or Ryzen 3 3200G owners — MSI explicitly states these two processors are not supported on this board.
PRO series helps users work smarter by delivering an efficient and productive experience. Featuring stable functionality and high-quality assembly, PRO series motherboards provide not only optimized professional workflows but also less troubleshooting and longevity.
Supports 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, up to 4400(OC) MHz.
Lightning Fast Experience: PCIe 4.0, Lightning Gen4 x4 M.2 with M.2 Shield Frozr, AMD Turbo USB 3.2 Gen 2
Premium Thermal Solution: Extended Heatsink Design with additional choke thermal pad and 7W/mK pad, and M.2 Shield Frozr are built for high performance system and non-stop works
Powerful Design: Core Boost, Digital PWM IC, 2oz Thickened Copper PCB, Creator Genie, DDR4 Boost
Flash BIOS Button: Simply use a USB key to flash any BIOS within seconds, without installing a CPU, memory or graphics card.
Core Boost Technology: Combining premium layout design, that is ready for unleashing the maximum performance.
7W/mK Thermal Pad: Premium 7W/mK thermal pad covered both MOSFET and chokes, provides better heat transfer to the heatsink.
Turbo USB: Featuring the TURBO USB 3.2 GEN 2 10Gbps, with reversible Type-C connector.
General
| Brand | MSI |
|---|---|
| Socket | AM4 |
| Chipset | AMD B550 |
| Form Factor | ATX |
| Dimensions | 305 × 244 mm (12 × 9.6") |
| Operating System | Windows 10 64-bit |
| Supported CPUs | AMD Ryzen 5000, 3000 (excl. Ryzen 5 3400G & Ryzen 3 3200G) and 4000 G-Series desktop processors |
Memory & Storage
| DIMM Slots | 4 (Dual Channel) |
|---|---|
| Max Memory | 128 GB |
| Memory Type | DDR4 |
| Memory Speed | 1866 / 2133 / 2400 / 2667 / 2800 / 2933 / 3000 / 3066 / 3200 / 3466 / 3600 / 3733 / 3866 / 4000 / 4133 / 4266 / 4400+ MHz (JEDEC & A-XMP OC) |
| M.2 Slots | 2 |
| M2_1 (CPU) | PCIe 4.0/3.0 x4 or SATA 6 Gb/s; 2242 / 2260 / 2280 / 22110 |
| M2_2 (Chipset) | PCIe 3.0 x4; 2242 / 2260 / 2280 |
| SATA III | 6 |
| RAID | 0, 1, 10 |
Expansion & Connectivity
| PCIe x16 Slots | 2 (Gen4 / Gen3) |
|---|---|
| PCIe x1 Slots | 2 |
| CrossFire | 2-Way AMD CrossFire |
| LAN | Realtek RTL8111H Gigabit |
| USB 3.2 Rear | 1× Gen 2 Type-C, 1× Gen 2 Type-A, 2× Gen 1 Type-A |
| USB 3.2 Front Headers | 1× Gen 1 Type-C, 2× Gen 1 Type-A |
| USB 2.0 Rear | 4 |
| USB 2.0 Front Headers | 4 |
| TPM Header | 1 |
Audio & Display
| Audio Codec | Realtek ALC892 / ALC897 |
|---|---|
| Audio Channels | 7.1-Channel HD Audio |
| DisplayPort | 1× DisplayPort, max 4096×2160 @ 60 Hz |
| HDMI | 1× HDMI 2.1, max 4096×2160 @ 60 Hz, HDCP 1.4 & 2.3 |
| Max Shared Memory | 16 GB |
| DirectX | 12 |
Shipping
All our products are shipped from the United Kingdom within 24 to 48 hours of purchase. See our Shipping and Returns page for full details.
Returns
- Tech Syndicate offers a full money-back guarantee on all purchases made in our store. If you are not satisfied with your purchase, we will provide a full refund, no questions asked.
- Refunds are available within 45 days of delivery.
- After the 45-day period you are no longer eligible for a refund, so we encourage you to try the product within the first few weeks to make sure it fits your needs.