Motherboards

MSI PRO B850M-A

Supports AMD Ryzen™ 9000 / 8000 / 7000 Series Desktop Processors
Supports DDR5 Memory, Dual Channel DDR5 8200+ MT/s (OC)
Ultra Performance: Direct 8+2+1 Power System 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
EZ DIY: EZ M.2 Shield Frozr II, EZ M.2 Clip II, and EZ PCIe Clip II
5G LAN: 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 and Lightning Gen 5 x4 M.2
Audio Boost: Reward your ears with studio-grade sound quality for the most immersive gaming experience

Category: Motherboards Brand: MSI

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Specification	Details
Chipset	AMD B850
CPU	Supports AMD Ryzen 9000 / 8000 / 7000 Series Desktop Processors Socket AM5
Memory
Configuration	4x DDR5 UDIMM, Maximum Memory Capacity 256GB
Memory Support	DDR5 8200 – 5600 (OC) MT/s / 5600 – 4800 (JEDEC) MT/s
Ryzen 9000 Series Max Overclocking Frequency	1DPC 1R: Up to 8200+ MT/s 1DPC 2R: Up to 6400+ MT/s 2DPC 1R: Up to 6400+ MT/s 2DPC 2R: Up to 6000+ MT/s
Features	Supports AMD POR Speed and JEDEC Speed Supports Memory Overclocking and AMD EXPO Supports Dual-Channel Mode Supports Non-ECC, Un-buffered Memory Supports CUDIMM, Clock Driver Bypass Mode Only*
Notes	* 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 only have single-sided latches. – Memory compatibility and supported speeds depend on CPU and configuration. Visit https://www.msi.com/support/ for more information.
Onboard Graphics
Ports	1x HDMI Supports HDMI 2.1, maximum resolution 4K 60Hz* 1x DisplayPort Supports DisplayPort 1.4, maximum resolution 4K 60Hz* *Available only on processors featuring integrated graphics. Graphics specifications may vary depending on CPU installed.
Expansion Slots
Slots	2x PCI-E x16 Slots 1x PCI-E x1 Slot PCI_E1 Gen PCIe 5.0 supports up to x16 (From CPU) PCI_E2 Gen PCIe 3.0 supports up to x1 (From Chipset) PCI_E3 Gen PCIe 4.0 supports up to x4 (From Chipset)
PCI_E1 Slot	– PCIe 5.0 x16 (Ryzen 9000 / 7000) – PCIe 4.0 x8 (Ryzen 8700 / 8600 / 8400) – PCIe 4.0 x4 (Ryzen 8500 / 8300)
Audio
Codec	Realtek ALC897
Channels	7.1-Channel High Definition Audio
Storage
Configuration	2x M.2 M.2_1 (From CPU): PCIe 5.0 x4, supports 2280/2260 devices M.2_2 (From CPU): PCIe 4.0 x4, supports 2280/2260 devices 4x SATA 6G
M.2_1 Slot	– PCIe 5.0 x4 (Ryzen 9000 / 7000) – PCIe 4.0 x4 (Ryzen 8000)
M.2_2 Slot	– PCIe 4.0 x4 – PCIe 4.0 x2 (Ryzen 8500 / 8300)
Notes	* Please refer to the manual for M.2 SSD heatsink restrictions.
RAID
Support	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
Configuration	4x USB 2.0 (Front) 3x USB 5Gbps Type-A (Rear) 2x USB 5Gbps Type-A (Front) 3x USB 10Gbps Type-A (Rear) 2x USB 10Gbps Type-C (Rear) 1x USB 10Gbps Type-C (Front)
LAN
Port	Realtek 8126VB 5G LAN
Internal I/O
Connectors	1x ATX Power (ATX_PWR) 2x CPU Power (CPU_PWR) 1x PCIE Power (8-pin) 1x CPU Fan 1x Combo Fan (Pump_Sys Fan) 3x System Fan 2x Front Panel (JFP) 1x Chassis Intrusion (JCI) 1x Front Audio (JAUD) 1x COM Port (JCOM) 1x Tuning Controller Connector (JDASH) 3x Addressable V2 RGB (JARGB_V2) 1x RGB LED (JRGB) 1x TPM Header (Supports TPM 2.0) 4x USB 2.0 Ports 2x USB 5Gbps Type-A Ports 1x USB 10Gbps Type-C Port
LED Features
Indicators	4x EZ Debug LED 1x EZ Memory Detection LED
Wireless LAN & Bluetooth
Type	Wi-Fi 7
Module	Pre-installed in the M.2 (Key-E) Slot
Performance	Supports MU-MIMO TX/RX, 2.4GHz / 5GHz / 6GHz* (160MHz) up to 2.9Gbps Supports 802.11 a / b / g / n / ac / ax / be Supports Bluetooth 5.4**, MLO, 4KQAM
Notes	* 6GHz band support may depend on country regulations; Wi-Fi 7 enabled in Windows 11 version 24H2. ** Bluetooth version may update; refer to chipset vendor’s website for details. Bluetooth 5.4 available in Windows 11 version 24H2.
Back Panel Ports
Configuration	Clear CMOS Button DisplayPort USB 10Gbps Type-A USB 10Gbps Type-A USB 5Gbps Type-A 5G LAN Audio connectors Flash BIOS Button HDMI™ USB 10Gbps Type-C USB 5Gbps Type-A
Operating System
Support	Windows 11 64-bit
PCB Info
Form Factor	mATX
Dimensions	243.84mm x 243.84mm

Overview

MSI PRO B850M-A – Compact Reliability, Professional Strength

The MSI PRO B850M-A motherboard delivers the perfect blend of stability, performance, and efficiency for professionals, creators, and everyday users. Designed to support AMD Ryzen™ 9000 / 8000 / 7000 Series Desktop Processors, it provides exceptional computing power and platform reliability in a compact micro-ATX form factor.

With support for dual-channel DDR5 memory up to 8200+ MT/s (OC), this board ensures rapid data transfer speeds and smooth multitasking. Its Direct 8+2+1 Power System with 60A Smart Power Stages (SPS) and 8+4-pin CPU power connectors guarantees steady power delivery for demanding workloads, while Core Boost and Memory Boost technologies maximize overall efficiency and performance.

The 6-layer PCB crafted from 2oz thickened copper and server-grade materials enhances durability, heat dissipation, and signal stability, making it ideal for long-term, high-performance use.

Equipped with Frozr Guard technology, the PRO B850M-A features an extended heatsink, MOSFET thermal pads rated for 7W/mK, additional choke pads, and EZ M.2 Shield Frozr II — ensuring optimal cooling and uninterrupted system performance under heavy workloads.

For high-speed connectivity, the motherboard includes PCIe 5.0 and Lightning Gen 5 x4 M.2, delivering cutting-edge performance for storage and graphics expansion. The integrated 5G LAN solution provides secure, stable, and lightning-fast networking for professional and multimedia tasks.

User convenience is enhanced with EZ DIY features, including EZ M.2 Shield Frozr II, EZ M.2 Clip II, and EZ PCIe Clip II, simplifying the building and upgrading process. Additionally, Audio Boost technology ensures crystal-clear, studio-grade sound for immersive entertainment and gaming experiences.

Product Datasheet