Overview
The MSI PRO B840M-B is a professional-grade micro-ATX motherboard designed for business and productivity. Part of the MSI PRO series, it is engineered to support the latest Intel® Core™ Ultra Processors (Series 2) on the LGA 1851 socket. Combining high-quality components with Intel B840 chipset stability, this motherboard provides a reliable foundation for modern workstations, featuring support for DDR5 memory, PCIe 4.0 storage, and professional-grade diagnostics.
Key Features
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Core Boost & Memory Boost: Premium layout and digital power design to support more cores and provide better performance. Advanced technology to deliver pure data signals for the best performance and stability.
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Lightning Gen 4 Solution: Equipped with an M.2 slot supporting PCIe 4.0 x4 for maximum data transfer speeds up to 64Gb/s.
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Steel Armor: Protects VGA cards against bending and EMI for enhanced stability and durability of the PCIe slot.
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Audio Boost: High-quality audio components for studio-grade sound quality, ensuring an immersive audio experience.
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EZ Debug LED: Integrated on-board LEDs for simplified troubleshooting of key components during the boot process.
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Frozr AI Cooling: Automatically detects CPU and GPU temperatures and adjusts fan duty of system fans to a proper value.
-FEATURES-
- Supports AMD Ryzen™ 9000 / 8000 / 7000 Series Desktop Processors
- Supports DDR5 Memory, up to 8200+(OC) MHz
- Ultra Performance : Ultra Performance: Direct 8+2+1 Power System with 60A SPS, 8+4-pin CPU power connectors, Core Boost, Memory Boost, 6-layer PCB made by 2oz thickened copper and server-grade level material
- Frozr Guard: Extended Heatsink, MOSFET thermal pads rated for 7W/mK, additional choke thermal pads and EZ M.2 Shield Frozr II are built for high performance system and non-stop experience
- High-speed Connectivity: 5G LAN with Wi-Fi 7 Solution - The latest solution for professional and multimedia use, delivering secure, stable, and high-speed networking and data transmission
- Lightning Fast Game experience: PCIe 5.0 slot, Lightning Gen 5 x4 M.2, Front USB Type-C
- EZ DIY: EZ M.2 Shield Frozr II, EZ M.2 Clip II, EZ PCIe Clip II and EZ Antenna
- Audio Boost: Reward your ears with studio grade sound quality for the most immersive gaming experience
-SPECS-
Warranty : 3 years
Brand : MSI
Model : PRO B840M-B
Form Factor : mATX 243.84mm x 243.84mm
Operating system : Support for Windows® 11 64-bit, Windows® 10 64-bit
CPU :
Supports AMD Ryzen™ 9000/ 8000/ 7000 Series Desktop Processors
Chipset : AMD B840
Onboard Graphics :
1x HDMI™
Support HDMI™ 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.
Audio :
- Realtek® ALC897 Codec
- 7.1-Channel High Definition Audio
Ethernet :
- Realtek® RTL8125 2.5G LAN
-Storage Interface-
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)
RAID
Supports RAID 0, RAID 1 and RAID 10 for SATA storage devices
Supports RAID 0 and RAID 1 for M.2 NVMe storage devices
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 EXPOTM
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/.
Slot :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)
Back I/O Ports:

1. Clear CMOS Button
2. HDMI™
3. VGA
4. USB 5Gbps Type-A
5. 2.5G LAN
6. Audio connectors
7. Flash BIOS Button
8. USB 2.0
-Internal I/O Connectors-
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