MSI Pro B840M-B

Manufacturer: MSI

The MSI Pro B840M-B is a Micro-ATX motherboard designed around AMD's AM5 platform, pairing the B840 chipset with a compact form factor that suits both space-conscious builds and standard desktop configurations. It carries a 3-year warranty and includes RGB lighting along with a convenient BIOS reset button, making it a straightforward choice for users who value ease of maintenance alongside reliable platform support.

On the memory side, the board accommodates two DDR5 slots with a standard ceiling of 5600 MHz and overclocked speeds reaching up to 8000 MHz, with a maximum capacity of 128GB across dual channels. Storage connectivity includes four SATA 3 connectors and two M.2 sockets, complemented by RAID 0, 1, and 10 support. Rear I/O provides four USB 3.2 Gen 1 Type-A ports, two USB 2.0 ports, a USB Type-C connector, HDMI 2.1 and VGA video outputs, and a single RJ45 ethernet port. Expansion is handled by one PCIe 4.0 x16 slot and one PCIe x1 slot, while the board also features 7.1-channel audio with three audio connectors and a TPM header.

Pros

Supports DDR5 memory with overclocked speeds up to 8000 MHz, offering meaningful headroom for memory-sensitive workloads
Two M.2 sockets and four SATA 3 connectors provide a solid range of storage options within a compact form factor
RAID 0, 1, and 10 support adds flexibility for users who want either redundancy or striped storage setups
Includes a TPM connector, supporting hardware-based security configurations
Easy BIOS reset button simplifies troubleshooting without requiring additional tools
Backed by a 3-year warranty, which is a reasonable coverage period for a motherboard

Cons

Only two memory slots limit future upgrade paths, as both slots must be used to reach maximum capacity
No Wi-Fi or Bluetooth connectivity requires separate adapters for wireless use
Lacks USB 3.2 Gen 2 ports on the rear panel, limiting high-speed peripheral throughput
No DisplayPort output, restricting display connectivity to HDMI and VGA only
Does not support ECC memory, ruling out error-correcting memory configurations
Only three fan headers may be insufficient for builds requiring more active cooling control

Who is this for?

This board is a practical fit for users building a capable AMD AM5 desktop within a compact footprint, particularly those who want DDR5 memory support with overclocking headroom up to 8000 MHz without needing a high-end chipset. Its Micro-ATX form factor and dual M.2 sockets make it well-suited for space-efficient home or office builds where storage flexibility matters. Users who intend to run wired network setups and do not require wireless connectivity will find the included RJ45 port sufficient, and those who value straightforward maintenance will appreciate the onboard BIOS reset button and the three-year warranty backing the platform.

Who is this NOT for?

This board is a poor match for users who need high-speed USB connectivity, as it lacks USB 3.2 Gen 2 and USB 4 ports entirely, which can bottleneck fast external drives or modern peripherals. Builders targeting a wireless-first setup will need to source separate adapters since neither Wi-Fi nor Bluetooth is included. The two-memory-slot configuration also makes this board unsuitable for users planning incremental RAM upgrades over time, and the absence of ECC memory support rules it out for workloads that demand error-correcting memory, such as certain professional or data-sensitive applications.

General info:

CPU socket	AM5
chipset	B840
form factor	Micro-ATX
supports Wi-Fi	✕
Has Bluetooth	✕
HDMI version	HDMI 2.1
Easy to overclock	✓
has RGB lighting	✓
Easy to reset BIOS	✓
Has dual BIOS	✕
CPU sockets	1
Has integrated graphics	✕
warranty period	3 years
height	226 mm
width	243.8 mm
Has integrated CPU	✕

The MSI Pro B840M-B is built around the AM5 socket with a compatible B840 chipset, housed in a Micro-ATX form factor measuring 243.8 mm wide and 226 mm tall. It supports a single CPU and does not include an integrated CPU or integrated graphics. The board features HDMI 2.1 video output, RGB lighting, and a convenient BIOS reset button, while overclocking is supported to give users some flexibility over performance tuning. It does not include Wi-Fi or Bluetooth connectivity, nor does it offer a dual BIOS configuration. A 3-year warranty is included, adding a reasonable level of long-term coverage for the platform.

Memory:

maximum memory amount	128GB
RAM speed (max)	5600 MHz
overclocked RAM speed	8000 MHz
memory slots	2
DDR memory version	5
memory channels	2
Supports ECC memory	✕

The board supports DDR5 memory across two slots in a dual-channel configuration, with a maximum capacity of 128GB. Standard RAM speeds reach up to 5600 MHz, while overclocking can push that figure to 8000 MHz for users who want additional memory bandwidth. ECC memory is not supported on this platform.

Ports:

USB 3.2 Gen 2 ports (USB-A)	0
USB 3.2 Gen 1 ports (USB-A)	4
USB 3.2 Gen 2 ports (USB-C)	0
USB 3.2 Gen 1 ports (USB-C)	0
USB 2.0 ports	2
USB 3.2 Gen 2x2 ports	0
USB 4 40Gbps ports	0
USB 4 20Gbps ports	0
Thunderbolt 4 ports	0
Thunderbolt 3 ports	0
has an HDMI output	✓
DisplayPort outputs	0
RJ45 ports	1
Has USB Type-C	✓
eSATA ports	0
DVI outputs	0
has a VGA connector	✓
PS/2 ports	0

The rear I/O panel includes four USB 3.2 Gen 1 Type-A ports and two USB 2.0 ports for peripheral connectivity, along with a single USB Type-C port. Video output options consist of an HDMI port and a VGA connector, while DisplayPort, DVI, and eSATA outputs are absent. Network connectivity is handled by one RJ45 port. There are no Thunderbolt 3 or 4 ports, no USB 4 ports of any speed tier, and no PS/2 connectors.

Connectors:

USB 3.2 Gen 1 ports (through expansion)	2
USB 3.2 Gen 2 ports (through expansion)	0
USB 3.2 Gen 2x2 ports (through expansion)	0
USB-C 3.2 Gen 2 ports (through expansion)	0
USB 2.0 ports (through expansion)	4
SATA 3 connectors	4
fan headers	3
USB 3.0 ports (through expansion)	2
M.2 sockets	2
Has TPM connector	✓
U.2 sockets	0
Has mSATA connector	✕
SATA 2 connectors	0

Internal connectivity is well-covered, with four SATA 3 connectors and two M.2 sockets available for storage devices, while SATA 2, mSATA, and U.2 options are not present. USB expansion headers include two USB 3.2 Gen 1 ports, two USB 3.0 ports, and four USB 2.0 ports, though no Gen 2, Gen 2x2, or USB-C expansion headers are provided. The board also includes three fan headers and a TPM connector for security module support.

Expansion slots:

PCIe 4.0 x16 slots	1
PCIe 5.0 x16 slots	0
PCIe 3.0 x16 slots	0
PCIe x1 slots	1
PCI slots	0
PCIe 2.0 x16 slots	0
PCIe x4 slots	0
PCIe x8 slots	0

The board offers a modest but functional expansion layout, featuring one PCIe 4.0 x16 slot for a primary graphics card or similar full-length device, alongside one PCIe x1 slot for smaller add-in cards. There are no PCIe 5.0, PCIe 3.0, PCIe 2.0, PCIe x4, or PCIe x8 slots, and no legacy PCI slots are present.

Audio:

audio channels	7.1
Has S/PDIF Out port	✕
audio connectors	3

The board supports 7.1-channel audio output, accommodated through three analog audio connectors on the rear panel. An S/PDIF output port is not included.

Storage:

Supports RAID 1	✓
Supports RAID 10 (1+0)	✓
Supports RAID 5	✕
Supports RAID 0	✓
Supports RAID 0+1	✕

The board supports RAID 0, RAID 1, and RAID 10 configurations, covering common setups for both performance-oriented striping and redundancy-focused mirroring. RAID 5 and RAID 0+1 are not supported.

Final Verdict

The MSI Pro B840M-B is a straightforward AM5 Micro-ATX motherboard that delivers a focused set of capabilities for users building a compact, wired desktop around AMD's current platform. Its DDR5 support with overclocking up to 8000 MHz, dual M.2 sockets, and broad RAID support give it genuine utility for everyday and storage-conscious builds, while the onboard BIOS reset button and three-year warranty add practical long-term value. The board's limitations — notably the absence of wireless connectivity, USB 3.2 Gen 2 ports, and only two memory slots — mean it is best suited to users with modest expansion needs rather than those chasing high-throughput peripherals or wireless-first setups. For builders who know exactly what they need from an AM5 platform and are happy to work within those boundaries, the Pro B840M-B delivers a dependable and well-defined foundation.