MSI quietly added three new B550 motherboards to its AM4 lineup, one microATX model and two ATX boards. The new models are the PRO B550M WIFI6E, PRO B550-S, and B550-S WIFI6E, all targeting AMD's Ryzen 3000, 4000G and 5000 processors. The PRO B550M WIFI6E is the microATX model measuring 243.84 x 210 mm. MSI opted for a spartan layout with only a tiny radiator on top of the AMD B550 chipset. The motherboard has two DDR4 DIMM slots supporting memory up to 4600+ MT/s (OC). For expansion, there is one PCIe 4.0 x16 slot and two PCIe 3.0 x1 slots, with one M.2 slot and four SATA 6 Gb/s ports for storage. The M.2 slot runs at PCIe 4.0 x4, while the wireless connectivity is provided by a pre-installed Wi-Fi 6E module.

The PRO B550-S and B550-S WIFI6E are full-size ATX boards measuring 243.84 x 304.8 mm. MSI opted for a more robust cooling package with dedicated heatsinks for the VRM, chipset and M.2 slot. Both feature four DDR4 DIMM slots with support for up to 128 GB and up to 4800+ MT/s (OC). The boards have two PCIe x16 slots, one PCIe x1, two M.2 slots, and four SATA ports. The first M.2 slot supports PCIe 4.0 x4, while the second runs at PCIe 3.0 x4. There are USB 5 Gbps Type-A and Type-C ports, along with 10 Gbps Type-A and Type-C ports on the rear I/O. The B550-S WIFI6E adds a pre-installed Wi-Fi 6E module. All three boards use the Realtek ALC897 7.1-channel audio codec and Realtek RTL8111H Gigabit Ethernet. MSI has not yet announced pricing or international availability.