MSI refreshes AM4 lineup with new B550 DDR4 boards
MSI has added two more B550 motherboards to its AM4 lineup. The boards are the PRO B550M-P and PRO B550M-B , both micro-ATX models with DDR4 memory support and the AMD B550 chipset.
Although we learned about this update from Hardware & Co, it looks like MSI Japan already listed new B550 models in February, including the PRO B550M-B. However, it is a fact that AM4 remains active in 2026.
Source: MSI
AM4 first appeared in 2016 with AMD’s Bristol Ridge platform, before Ryzen arrived in 2017. Nearly 10 years later, vendors are still releasing or refreshing motherboards for the same socket. Although this is still unofficial, AMD seems to be planning a small anniversary update with the special 5800X3D SKU as we shared earlier.
The fact that AMD kept AM4 for this long is impressive, but also well-needed. The main reason why AM4 is still popular is DDR4 support, which keeps AM4 useful for lower-cost upgrades and office systems.
As for the actual boards, the PRO B550M-P is the stronger of the two boards. It has four DDR4 slots, up to 128GB memory support, two M.2 slots, PCIe 4.0 from the CPU and front USB Type-C. The PRO B550M-B uses two DDR4 slots with up to 64GB support, but it still has two M.2 slots and PCIe 4.0 support with compatible Ryzen processors.
The fact that we are seeing new AM4 motherboards in 2026 is not really a surprise. As you recall, motherboard vendors were expected to keep AM4 and DDR4 production active in 2026.
| Specifications | ||
|---|---|---|
| Spec | MSI PRO B550M-P | MSI PRO B550M-B |
| Socket | AM4 | AM4 |
| Chipset | AMD B550 | AMD B550 |
| Form factor | mATX | mATX |
| Memory | 4x DDR4 | 2x DDR4 |
| Max memory | 128GB | 64GB |
| PCIe x16 | PCIe 4.0 x16 | PCIe 4.0 x16 |
| M.2 slots | 2 | 2 |
| SATA | 4x SATA 6G | 4x SATA 6G |
| Rear display | HDMI, DisplayPort, VGA | HDMI, DisplayPort |
| LAN | 1GbE | 1GbE |
Source: MSI , MSI , Hardware & Co
