MSI

MSI PRO B840M-B AM5 Micro-ATX Motherboard - DDR5 128GB PCIe 4.0 2.5Gb LAN (Boxed)

SKU 4902 Brand MSI EAN13 4711377360166
AM5 micro-ATX motherboard for Ryzen 9000/8000/7000 CPUs. Supports DDR5 up to 128GB (2 slots, 8000+MT/s OC, EXPO), PCIe 4.0 x16, 2x M.2 Gen4, 4x SATA, 2.5Gb LAN, USB-C, Realtek audio, 7+2+1 VRM.
Motherboards - CPU Socket AMD AM5
Motherboards - Chipset AMD B840
Motherboards - Form Factor Micro-ATX
Motherboards - Memory Type DDR5
Motherboards - Memory Profile Support EXPO
Motherboards - Memory Slots 2
Motherboards - Max Memory Capacity 128 GB
Motherboards - Main Slot PCIe Version PCIe 4.0
Motherboards - Color Black
Motherboards - M.2 Slots 2
Motherboards - SATA Ports 4
Motherboards - USB-C Support Front Panel Type-C header Rear Type-C
Motherboards - RGB Headers 3-pin 5V ARGB
Motherboards - Wireless Connectivity None

The MSI PRO B840M-B is a business-oriented micro-ATX motherboard built on the AMD B840 chipset, designed for AMD Ryzen 9000, 8000, and 7000 Series processors with Socket AM5. It features a robust 7+2+1 phase digital power design with an 8-pin CPU connector, Core Boost technology, and 6-layer PCB with 2oz thickened copper for reliable performance under heavy loads.

Memory support includes 2x DDR5 DIMM slots with dual-channel operation up to 128GB capacity and overclocking potential to 8000+ MT/s (1DPC 1R). It supports AMD EXPO profiles, Memory Boost, and High-Efficiency Mode for optimized bandwidth and low latency. Storage options comprise 2x M.2 slots (PCIe 4.0 x4, up to 2280), 4x SATA 6Gb/s ports with RAID 0/1/10 support, plus PCIe 4.0 x16 slot for graphics and expansion.

Connectivity includes 2.5G Realtek RTL8125D LAN, Realtek ALC897 7.1-channel HD audio, rear USB 5Gbps Type-A/C, HDMI 2.1, DisplayPort, and multiple front-panel headers. EZ Debug LEDs, Flash BIOS button, and Frozr design enhance DIY assembly and stability. Ideal for productivity builds and AI-PCs.

  • CPU: AMD Ryzen 9000/8000/7000 Series (AM5)
  • Memory: 2x DDR5, 128GB max, 8000+ MT/s OC
  • Storage: 2x M.2 PCIe 4.0, 4x SATA, RAID 0/1/10
  • Network: 2.5Gb LAN
  • Form Factor: micro-ATX (226 x 243.84mm)
Supported CPU ModelsAMD Ryzen 9000 / 8000 / 7000 Series
SocketAM5
ChipsetAMD B840
BIOS256 Mbit
Form Factormicro ATX (226mm x 243.84mm)
Max Memory128 GB
Memory Slots2x DDR5 DIMM
Memory SpeedDDR5 8000+ MT/s (OC) / 5600-4800 JEDEC
Memory ChannelsDual Channel
Memory TypeNon-ECC, Un-buffered DDR5
LANRealtek RTL8125D 2.5 Gigabit Ethernet
Audio ChipRealtek ALC897 7.1 CH HD Audio
PCIe Slots1x PCIe 4.0 x16, others PCIe 4.0/3.0
M.2 Slots2 (PCIe 4.0 x4, up to 2280 M-key)
SATA Ports4x SATA 6Gb/s
RAID SupportSATA RAID 0/1/10, M.2 RAID 0/1
VRM Design7+2+1 Phase Digital Power (8-pin CPU)
USB RearUSB 5Gbps Type-A/C, USB 2.0
Video Outputs1x HDMI 2.1, 1x DisplayPort
RGB HeadersYes (3-pin 5V ARGB)
Weight1950 g (PCB)
ColorBlack