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MSI · AM5 · B840

MSI PRO B840M-B

Micro-ATX · DDR5 · 2 DIMMs · 7-phase VRM

Quality
44
VRM
22
Value
92
Amazon
$90
MSI PRO B840M-B
View MSI PRO B840M-B Gallery in high resolution
$90
Available Updated 3 days, 8 hours ago Prime FBA
Overall43.6
VRM22.0
Chipset71.0
Expansion / storage51.0
Connectivity34.0
Audio40.0
Quality / price92.1
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Written analysis

MSI PRO B840M-B at a glance

The MSI PRO B840M-B uses the Micro-ATX form factor, AM5 socket, and AMD B840 chipset. This is a balanced mainstream platform: enough expansion and connectivity for a performance PC without paying only for flagship extras.

Memory support is DDR5 across 2 DIMM slots, with up to 128 GB and rated overclocked speeds up to 8000 MT/s. XMP / EXPO memory-profile support is recorded for easier tuning.

Best fit: a mainstream gaming, home, or office system with moderate expansion needs.

Power delivery

The calculated VRM score is 22.0, placing the power delivery in the basic class. The board lists 7 CPU power phases, 60 A power stages in a 7 + 2 +1 layout. CPU power input is listed as 1. Keep it paired with lower-power processors and avoid sustained overclocked loads.

Expansion and storage

The expansion and storage score is 51.0: focused on the essentials. The platform supports PCIe 4.0. Physical expansion includes 1 ×16 slot, and 1 ×1.

On-board storage consists of 2 M.2 slots supporting PCIe 4.0 x4, PCIe 4.0 x2 and 4 SATA ports. Supported M.2 lengths are listed as 2280, 2260. The two-slot layout covers a typical OS-and-games or OS-and-project-drive setup.

Connectivity and rear I/O

The connectivity score is 34.0, rated essential. There is no recorded onboard Wi-Fi ; wired networking is Realtek ® 8125D 2.5G LAN at up to 2500 Mbps. The recorded USB provision is 6 rear connections and 7 front-panel connections. The specification sheet below separates every USB speed and connector type.

Display connectivity includes HDMI 2.1. These motherboard outputs require a processor with integrated graphics.

Audio

The audio score is 40.0. This is a standard onboard solution using Realtek ALC897. It covers normal gaming and communication; demanding headphones or production work still benefit from an external interface.

Buying verdict

Overall quality is 43.60, a basic but usable result for office, media, and budget gaming systems.

At the recorded Amazon price, the quality-to-price score is 92.1—an excellent value relative to the other boards in the catalog.

Board data

Full specifications

Platform, expansion, storage, rear I/O, internal headers, networking, audio, and board controls in one sheet.

General

Manufacturer
MSI
Motherboard
MSI PRO B840M-B
Chipset / socket
AMD B840 / AM5
Form factor
Micro-ATX
Launch price
—
Amazon price
$90
Availability
In stock
Price updated
3 days, 8 hours ago

VRM

CPU phases
7 (60 A)
Power design
7 + 2 +1
EPS connector
1

Memory

Type / slots
DDR5 / 2 DIMMs
Max capacity / OC
128 GB / 8000 MT/s
Per DIMM
64 GB
XMP / EXPO
Yes

PCIe

Supported version
PCIe 4.0
x16 physical
1
x16 Gen 4
1
x1 physical
1
x1 Gen 3
1

Storage

M.2 slots
2
M.2 lengths
2280, 2260
M.2 modes
PCIe 4.0 x4, PCIe 4.0 x2
SATA ports
4

Display outputs

HDMI
Yes · 2.1 · 4K 60Hz
DisplayPort
No
USB-C DisplayPort
No

USB

Rear USB 2.0
2
Rear USB 3.2 Gen 1 Type-A 5 Gbps
4
Front USB 2.0
4
Front USB 3.2 Gen 1 Type-A 5 Gbps
2
Front USB 3.2 Gen 1 Type-C 5 Gbps
1
Header USB 2.0
4
Header USB 3.2 Gen 1 Type-A 5 Gbps
3

Networking

Ethernet
Realtek ® 8125D 2.5G LAN
LAN ports
1
LAN speed
2500 Mbps
Wi-Fi
Not included
Bluetooth
No

Audio

Chipset
Realtek ALC897
Analog jacks
—
Gold-plated jacks
No
Optical S/PDIF
No
Spatial audio
Rear output

Buttons

BIOS flashback
Yes
Clear CMOS
Yes
Q-Flash Plus
No
Smart button
No
Onboard start / reset
No

Additional information

CPU support
Supports AMD Ryzen™ 9000/ 8000/ 7000 Series Desktop Processors, Socket AM5,
OS support
Support for Windows ® 11 64-bit,
Memory notes
Supports AMD EXPO TM. For Ryzen™ 9000 Series Processors, max overclocking frequency is up to 8000+ MT/s for 1DPC 1R and up to 7200+ MT/s for 1DPC 2R. Supports AMD POR Speed and JEDEC Speed. Supports Un-buffered memory. Supports CUDIMM in Clock Driver bypass mode only, but support and boot frequency may vary by CPU series and require future BIOS updates. The DIMM slots have single-sided latches. Memory compatibility and supported speeds can vary depending on the CPU and memory configuration.
Display notes
Includes 1x VGA port, supporting a maximum resolution of 2048x1536 50Hz, 2048x1280 60Hz, or 1920x1200 60Hz. Video outputs are available only on processors featuring integrated graphics. Graphics specifications may vary depending on the CPU installed.
Expansion notes
PCI_E1 Gen PCIe 4.0 supports up to x16 (From CPU). PCI_E2 Gen PCIe 3.0 supports up to x1 (From Chipset). The PCI_E1 slot supports PCIe 4.0 x16 for Ryzen™ 9000/7000 Series processors, PCIe 4.0 x8 for Ryzen™ 8700/8600/8400 Series processors, and PCIe 4.0 x4 for Ryzen™ 8500/8300 Series processors.
M.2_1
4.0 4 · 2280, 2260 · CPU
M.2_2
4.0 4 · 2280, 2260 · CPU — The M.2_2 slot supports up to PCIe 4.0 x2 when used with Ryzen™ 8500/8300 Series processors.
RAID
SATA / PCIe (0, 1, 10)
Audio notes
7.1-Channel High Definition Audio
Fan / RGB headers
1 CPU · — OPT · — AIO · 2 chassis · 3 ARGB · 1 RGB
Other headers
Front audio · System panel · TPM
Accessories
,
Dimensions
mATX, 226mmx243.84mm,

Extracted notes sit here. Official manufacturer copy is at the bottom of the page.

Amazon

Price history

Nearby quality

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VRM fit

VRM-appropriate CPUs

AM5 processors whose TDP sits in this board’s VRM window. Socket match is required; chipset extras still matter on sTR5. This is a power-delivery filter, not a ranked CPU guide.

Open AM5 CPUs in the CPU table

Discussion

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Vendor copy

Official manufacturer data

Raw manufacturer text kept for reference. Structured specs above are extracted from this copy and are the source for scores and tables.

CPU support

Supports AMD Ryzen™ 9000/ 8000/ 7000 Series Desktop Processors, Socket AM5,

Memory

2x DDR5 UDIMM, Maximum Memory Capacity 128GB, Memory Support DDR5 8000 - 5600 (OC) MT/s / 5600 - 4800 (JEDEC) MT/s, Ryzen™ 9000 Series Processors max. overclocking frequency:,
• 1DPC 1R Max speed up to 8000+ MT/s,
• 1DPC 2R Max speed up to 7200+ MT/s, , Supports AMD POR Speed and JEDEC Speed,
Supports Memory Overclocking and AMD EXPO TM,
Supports Dual-Channel mode,
Supports Non-ECC, Un-buffered memory,
Supports CUDIMM, Clock Driver bypass mode only*, , * CUDIMM support and POR boot frequency may vary by CPU series, with manual overclocking available after boot. Certain CPUs may fail to boot, but future BIOS updates will improve compatibility., • The DIMM slots on this motherboard have single-sided latches.,
• Memory compatibility and supported speeds can vary depending on the CPU and memory configuration. For detailed information, please refer to the Memory Compatibility List available on the product’s Support page or visit https://www.msi.com/support/.,

Graphics

1x HDMI™, Support HDMI TM 2.1, maximum resolution of 4K 60Hz*, 1x VGA, Support VGA, maximum resolution of 2048x1536 50Hz, 2048x1280 60Hz, 1920x1200 60Hz*, *Available only on processors featuring integrated graphics. Graphics specifications may vary depending on the CPU installed.,

Expansion slots

1x PCI-E x16 slot, 1x PCI-E x1 slot, PCI_E1 Gen PCIe 4.0 supports up to x16 (From CPU), PCI_E2 Gen PCIe 3.0 supports up to x1 (From Chipset), ,
PCI_E1 slot,
• Supports PCIe 4.0 x16 (For Ryzen™ 9000/ 7000 Series processors),
• Supports PCIe 4.0 x8 (For Ryzen™ 8700/ 8600/ 8400 Series processors),
• Supports PCIe 4.0 x4 (For Ryzen™ 8500/ 8300 Series processors),

Storage

2x M.2, M.2_1 Source (From CPU) supports up to PCIe 4.0 x4 , supports 2280/2260 devices, M.2_2 Source (From CPU) supports up to PCIe 4.0 x4 , supports 2280/2260 devices, 4x SATA 6G, ,
M2_2 slot,
• Supports up to PCIe 4.0 x4,
• Supports up to PCIe 4.0 x2 (For Ryzen™ 8500/ 8300 Series processors),, Supports RAID 0, RAID 1 and RAID 10 for SATA storage devices,
Supports RAID 0 and RAID 1 for M.2 NVMe storage devices,

USB

2x USB 2.0 (Rear), 4x USB 2.0 (Front), 4x USB 5Gbps Type A (Rear), 2x USB 5Gbps Type A (Front), 1x USB 5Gbps Type C (Front),

Internal I/O

1x Power Connector(ATX_PWR), 1x Power Connector(CPU_PWR), 1x CPU Fan, 2x System Fan, 2x Front Panel (JFP), 1x Chassis Intrusion (JCI), 1x Front Audio (JAUD), 1x Com Port (JCOM), 3x Addressable V2 RGB LED connector (JARGB_V2), 1x RGB LED connector(JRGB), 1x TPM pin header(Support TPM 2.0), 4x USB 2.0 ports, 2x USB 5Gbps Type A ports, 1x USB 5Gbps Type C ports,

Rear I/O

Clear CMOS Button HDMI™ VGA USB 5Gbps Type-A 2.5G LAN Audio connectors Flash BIOS Button USB 2.0,

Audio

Realtek ® ALC897, 7.1-Channel High Definition Audio,

Accessories

,

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