MSI · Motherboard

MSI PRO B550-S

B550 · AM4 · ATX · DDR4

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Chipset B550
Form factor ATX
Memory slots 4
Max memory 128 GB
Socket AM4
Memory type DDR4

MSI PRO B550-S is an ATX and B550 chipset motherboard for AM4 processors and DDR4 memory. It came out in 2026.

Released: 2026-10-06
Socket: AM4

Specifications

Key specs

Chipset: B550
Form factor: ATX
Memory slots: 4
Max memory: 128 GB
Socket: AM4
Memory type: DDR4
Released: 2026-10-06
Part number: PRO B550-S

Processor

Processor manufacturer: AMD
Processor socket: Socket AM4
Compatible processor series: AMD Ryzen 3000 Series, AMD Ryzen 4000 Series, AMD Ryzen 5000 Series
Supported processor sockets: Socket AM4

Memory

Supported memory types: DDR4-SDRAM
Number of memory slots: 4
Memory slots type: DIMM
Memory channels: Dual-channel
ECC сompatibility: Non-ECC
Supported memory clock speeds: 2667,2800,2933,3000,3066,3200,3466,3600,3733,3866,4000,4133,4266,4400,4533,4600,4733,4800,4866 MHz
Supported memory clock speed (max): 4866 MHz
Maximum internal memory: 128 GB
Unbuffered memory: Yes

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Storage controllers

Supported storage drive types: HDD & SSD
Supported storage drive interfaces: M.2, Micro SATA III
Number of HDDs supported: 4
Number of storage drives supported: 6
RAID support: Yes
RAID levels: 0, 1, 10

Graphics

Parallel processing technology support: Not supported
On-board graphics card: Yes

Internal I/O

USB 2.0 connectors: 4
USB 3.2 Gen 1 (3.1 Gen 1) connectors: 2
USB 3.2 Gen 2 (3.1 Gen 2) connectors: 1
Number of SATA III connectors: 4
Total number of SATA connectors: 4
Front panel audio connector: Yes
Front panel connector: Yes
ATX Power connector (24-pin): Yes
CPU fan connector: Yes
Number of CPU fan connectors: 1
Number of chassis fan connectors: 4
EPS power connector (8-pin): Yes
TPM connector: Yes
12V power connector: Yes
RGB LED pin header: Yes

Rear panel I/O ports

USB 2.0 ports quantity: 4
USB 3.2 Gen 1 (3.1 Gen 1) Type-A ports quantity: 2
USB 3.2 Gen 2 (3.1 Gen 2) Type-A ports quantity: 1
USB 3.2 Gen 2 (3.1 Gen 2) Type-C ports quantity: 1
Ethernet LAN (RJ-45) ports: 1
HDMI ports quantity: 1
HDMI version: 1.4

Network

Ethernet LAN: Yes
Ethernet interface type: Gigabit Ethernet
LAN controller: Realtek RTL8111H

Features

Motherboard chipset: AMD B550
Audio chip: Realtek ALC897
Audio output channels: 7.1 channels
PC health monitoring: CPU, Fan, Temperature
Component for: PC
Motherboard form factor: ATX
Motherboard chipset family: AMD
Power source type: ATX
Windows operating systems supported: Windows 10, Windows 11

Expansion slots

PCI Express x1 (Gen 3.x) slots: 1
PCI Express x16 (Gen 3.x) slots: 1
PCI Express x16 (Gen 4.x) slots: 1
Number of M.2 (M) slots: 2
1st M.2 largest key size: 22110
1st M.2 highest PCI Express generation: 4.0
2nd M.2 largest key size: 2280
2nd M.2 highest PCI Express generation: 3.0

BIOS

BIOS type: UEFI
BIOS memory size: 256 Mbit
ACPI version: 6.0
System Management BIOS (SMBIOS) version: 2.8

Weight & dimensions

Width: 243.8 mm
Depth: 304.8 mm

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Compatible processors

AM4 socket

AMD Ryzen 5 56006 cores · 12 threads
AMD Ryzen 5 55006 cores · 12 threads
AMD Ryzen 5 5600G6 cores · 12 threads
AMD Ryzen 7 5700X8 cores · 16 threads
AMD Ryzen 5 5600X6 cores · 12 threads
AMD Ryzen 5 5500F6 cores · 12 threads
AMD Ryzen 5 5600F6 cores · 12 threads
AMD Ryzen 5 5600T6 cores · 12 threads

Compatible memory

DDR4

Kingston FURY Beast 8GB (1x8) DDR4-3200 CL168 GB (1x8) · DDR4
Kingston FURY Beast 16GB (2x8) DDR4-3200 CL1616 GB (2x8) · DDR4
VeloxStor 7004-DDR, 8 GB, 1 x 8 GB, DDR4, 3200 MT/s, 288-pin DIMM8 GB (1x8) · DDR4
VeloxStor 7005-DDR, 16 GB, 1 x 16 GB, DDR4, 3200 MT/s, 288-pin DIMM16 GB (1x16) · DDR4
VeloxStor 7006-DDR, 32 GB, 1 x 32 GB, DDR4, 3200 MT/s, 288-pin DIMM32 GB (1x32) · DDR4
VeloxStor 7007-DDR, 8 GB, 1 x 8 GB, DDR4, 3200 MT/s, 288-pin DIMM8 GB (1x8) · DDR4
VeloxStor 7008-DDR, 16 GB, 1 x 16 GB, DDR4, 3200 MT/s, 288-pin DIMM16 GB (1x16) · DDR4
Biwin BXH41632HW1-D16EW 16 GB DDR4 Memory16 GB (2x8) · DDR4

About this product

PRO B550-S

PRO B550-S is engineered with PCIe 4.0 M.2, M.2 Shield Frozr, Frozr AI Cooling, and Front Type-C, ready for the AMD Ryzen™ 5000 series processors. The PRO Series is tailored to professionals from all walks of life. The lineup features impressive performance and high quality, while aiming to provide users incredible experience. Users who care about productivity and efficiency can definitely count on the MSI PRO Series to assist you with multitasking and increasing efficiency. MSI motherboards circuitry ensure the case standoff keep out zones are pure and clean. Moreover, the protective paint is printed around each screw hole to prevent parts from being scratched or damaged to the motherboard.

EZ DEBUG LED

Onboard LEDs will indicate the source of the problem so you know exactly where to look to get up and running again.

HEADER WITH DIFFERENT COLOR

To better differentiate between pin headers for different purposes, mark the pump sys header and the ARGB headers in gray, enabling users to manage cables more efficiently. A host of features inject artificial intelligence into key aspects of your computing experience to make smarter, real-time optimizations.

User manual (PDF) · Datasheet (PDF)

PRO B550-S vs similar motherboards

	MSI PRO B550-S	MSI B550 GAMING	MSI PRO B550M-P	MSI PRO B550-S WIFI6E
Chipset	B550	B550	B550	B550
Form factor	ATX	ATX	ATX	ATX
Memory slots	4	4	4	4
Max memory	128 GB	128 GB	128 GB	128 GB
Socket	AM4	AM4	AM4	AM4
Memory type	DDR4	DDR4	DDR4	DDR4
Released	2026	2026	2026	2026