ASUS Prime B550M-A WiFi II Motherboard: features, specs and who it suits

The ASUS Prime B550M-A WiFi II is a micro ATX motherboard for AMD's AM4 platform. It uses the B550 chipset and pairs a compact board size with PCIe 4.0, two M.2 slots and built-in WiFi 6. It is a base for a compact or mid-size desktop built around a Ryzen processor.

The AM4 socket and which processors fit

AM4 is the socket used across several Ryzen generations. ASUS lists support for Ryzen 5000, 5000 G, 4000 G and 3000 series desktop processors. Processor support can depend on the BIOS version on the board, so check the maker's support list for your exact chip. A G-series processor has integrated graphics, which is what the board's video outputs need.

Memory: four DDR4 slots

There are four DDR4 slots, supporting up to 128 GB in total. More slots mean you can add memory in stages, and a higher ceiling matters for editing, virtual machines and large projects. ASUS also mentions its OptiMem II design for using the memory well. Check the supported speeds and module lists in the manual.

PCIe 4.0 and two M.2 slots

PCIe 4.0 doubles the per-lane bandwidth of PCIe 3.0. It matters most for fast NVMe SSDs and recent graphics cards. The board has two M.2 connectors for SSDs, so you can keep a system drive and a second drive for games or files without a separate adapter. Check which slots run at which speeds, and whether using one disables SATA ports, in the manual.

Cooling and connectivity

ASUS lists heatsinks on the chipset (PCH) and the VRM, which delivers power to the processor, as well as hybrid fan headers and the Fan Xpert 2+ utility. The VRM heatsink helps keep long gaming or work sessions stable.

For networking there are a Realtek 1 Gbps Ethernet port and WiFi 6 (802.11ax). Video outputs are HDMI 2.0, DisplayPort, DVI-D and D-Sub. Storage and data include SATA 6 Gbps and a USB 3.2 Gen 2 Type-A port.

RGB lighting support

The board has an onboard addressable Gen 2 header and RGB headers for LED strips, which sync with Aura Sync-capable hardware. You can ignore it if you don't want lighting.

Who it suits

It suits builders putting together a compact AM4 system, upgraders moving to a Ryzen 5000 chip, and anyone who wants wireless built in without a separate card.

What to check before you buy

• Processor and BIOS: confirm your CPU is on the support list and whether a BIOS update is needed.
• Case size: micro ATX fits in micro ATX and larger cases. Board dimensions are about 9.6 x 9.6 inches.
• Memory: it takes DDR4 only, not DDR5.
• Storage: check the M.2 slot speeds and sizes for your SSDs.
• Cooler: make sure your cooler supports AM4 mounting.

The short version

• A micro ATX AM4 board with the AMD B550 chipset.
• Supports Ryzen 5000, 5000 G, 4000 G and 3000 series processors.
• Four DDR4 slots, up to 128 GB, with two M.2 slots and PCIe 4.0.
• WiFi 6, 1 Gbps Ethernet, HDMI, DisplayPort, DVI-D and D-Sub.
• VRM and chipset heatsinks, plus Aura Sync RGB headers.

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