ASUS PRIME B840M-A-CSM AM5 Micro-ATX Motherboard

Description

Overview

The ASUS PRIME B840M-A-CSM is a Corporate Stable Model (CSM) micro‑ATX motherboard for AMD AM5 systems. It’s designed for reliable business and general‑purpose builds that need modern connectivity and DDR5 memory support without the extras of consumer gaming variants.

Key features

• Socket & chipset: AMD Socket AM5 with the B840 chipset; supports AMD Ryzen™ 7000, 8000 and 9000 series desktop processors (supports CPUs up to 170W).
• Memory: 4 × DDR5 DIMM slots, up to 256GB total, dual‑channel; supports AMD EXPO profiles and ASUS Enhanced Memory Profile (AEMP); memory overclocking beyond stock (ASUS lists support up to 7600+ MT/s OC depending on CPU).
• Storage: Three M.2 slots (M.2_1 and M.2_2 support PCIe 4.0 x4 with compatible CPUs; M.2_3 provided by the B840 chipset supports PCIe 3.0 x4) plus four SATA 6Gb/s ports.
• Expansion & graphics: 1 × PCIe 4.0 x16 primary slot (operation depends on CPU), plus two additional PCIe x16 (electrical x1) slots for add‑in cards.
• Networking & I/O: Realtek 2.5Gb Ethernet; rear I/O includes 2 × USB 10Gbps Type‑A, 1 × USB 5Gbps Type‑C, multiple USB 2.0 ports, 2 × DisplayPort, 1 × HDMI, BIOS FlashBack™ button and 3‑pin audio jacks.
• Design & reliability: Pre‑mounted I/O shield, M.2 heatsink, VRM cooling, BIOS FlashBack and ASUS 5X Protection III features.

This CSM SKU does not include onboard Wi‑Fi (ASUS offers separate “WIFI” variants if wireless is required). For CPU compatibility and the latest BIOS updates consult ASUS support and the official CPU support list before assembly.