ASUS PRIME B840M-A-CSM MOTHERBOARD

ASUS PRIME B840M-A-CSM MOTHERBOARD 

Core Features
CPU Support:

AMD Ryzen 9000, 8000, and 7000 Series Desktop Processors (Socket AM5)

Chipset:

AMD B840

Memory:

4× DDR5 DIMM slots (up to 256GB)

Supports up to 7600+ MT/s (OC)

AMD EXPO and ASUS AEMP profiles supported

Dual channel, ECC/Non-ECC unbuffered DDR5

Graphics Outputs:

2× DisplayPort 1.4 (up to 8K@30Hz)

1× HDMI 2.1 (4K@60Hz)
[Integrated GPU depends on the CPU]

Expansion Slots:

1× PCIe 4.0 x16 (full x16 with Ryzen 9000/7000; x8/x4 with Ryzen 8000)

2× PCIe 3.0 x16 (x1 mode from chipset)

Storage:

3× M.2 slots
(PCIe 4.0 or PCIe 3.0 depending on slot/CPU)

4× SATA 6Gb/s ports

Supports AMD RAIDXpert2 for RAID setups

Networking:

Realtek 2.5Gb Ethernet with ASUS LANGuard

USB Ports:

Rear:

2× USB 3.2 Gen2 (10Gbps) Type-A

1× USB 3.2 Gen1 (5Gbps) Type-C

4× USB 2.0

Front/Internal:

USB 5Gbps Type-C connector

Additional headers for USB 5Gbps ×2 and USB 2.0 ×4

Audio:

Realtek 7.1 Surround HD Audio Codec

High-end capacitors, dedicated PCB layers, shielding

S/PDIF header available

Other Highlights
Internal I/O:

BIOS FlashBack, clear CMOS, 3× Addressable Gen 2 RGB headers

1× COM port header (useful for industrial/business setups)

TPM 2.0 SPI header

Special Features:

ASUS 5X Protection III (strong durability suite)

M.2 heatsink and VRM heatsinks

Q-LED Core (diagnostic LEDs)

Pre-mounted I/O shield

Remote Management:

Supports ASUS Control Center Express (ACCE) for IT environments

Form Factor:

micro-ATX (24.4 cm × 24.4 cm)

Operating Systems Supported:

Windows 11 / Windows 10 64-bit

Included Accessories
2× SATA cables

M.2 rubber package and screws

Quick Start Guide

ACCE Activation Card

Comments
This motherboard is clearly built for stability, long-term support, and ease of maintenance, targeting professional, office, or business users, but it's also powerful enough for mainstream builds thanks to DDR5 and PCIe 4.0 support.

If you plan to use a Ryzen 8000 CPU, just note that the PCIe lanes and storage bandwidths slightly vary compared to the Ryzen 9000/7000 series.