ASUS Prime B840M-A CSM DDR5 AMD Motherboard

The ASUS Prime B840M-A CSM is a micro-ATX motherboard built on the AMD B840 chipset with an AM5 socket, designed for AMD Ryzen 9000, 8000, and 7000 series desktop processors. Its compact 9.6-inch × 9.6-inch footprint suits space-conscious builds without compromising on connectivity or performance headroom. Memory flexibility is a key strength. Four DDR5 DIMM slots support up to 192 GB of unbuffered DDR5 RAM in a dual-channel configuration, with overclocked speeds reaching 7600+ MT/s when paired with compatible Ryzen 9000 or 8000 series CPUs. Both AMD EXPO and ASUS AEMP (ASUS Enhanced Memory Profile) are supported, giving enthusiasts one-click memory tuning options for entry-level and high-speed kits alike. Storage throughput is handled by three M.2 Key-M slots. Two slots (M.2_1 and M.2_2) run at PCIe 4.0 x4 for up to 64 Gbps transfers with Ryzen 9000 and 7000 processors, while the third (M.2_3) operates via the B840 chipset at PCIe 3.0 x4. Four SATA 6 Gb/s ports round out internal storage, with AMD RAIDXpert2 RAID support (0/1/5/10 depending on processor series). Display output on the rear panel includes two DisplayPort 1.4 outputs (supporting up to 8K@30Hz) and one HDMI 2.1 port (4K@60Hz), useful for builds using AMD APUs or integrated graphics. Networking is provided by a Realtek 2.5 Gb Ethernet controller paired with ASUS LANGuard surge protection. USB connectivity spans rear and front connections: the back panel provides two USB 10 Gbps Type-A ports, one USB 5 Gbps Type-C, and four USB 2.0 Type-A ports. The front panel includes a USB 5 Gbps Type-C connector, a USB 5 Gbps header (for two additional ports), and two USB 2.0 headers (for four additional ports). Audio is handled by a Realtek High Definition CODEC delivering 7.1 surround sound with up to 24-bit/192 kHz playback, backed by audio shielding, premium capacitors, and dedicated audio PCB layers. Thermal management is supported through an M.2 heatsink, VRM heatsink, and multiple hybrid fan headers (one CPU fan, one CPU OPT, two chassis fan), all manageable via ASUS Fan Xpert 2+ software. The board carries ASUS 5X Protection III safeguards including DIGI+ VRM, LANGuard, overvoltage protection, SafeSlot Core+, and a stainless-steel I/O panel. Three addressable Gen 2 (ARGB) headers enable Aura Sync RGB customisation. A pre-mounted I/O shield, BIOS FlashBack button, and Q-Design features (Q-DIMM, Q-LED, Q-Slot) simplify the build process. ASUS Control Center Express (ACCE) enables IT management and remote administration. Key Specifications: – Form Factor: micro-ATX, 9.6 in × 9.6 in (24.4 cm × 24.4 cm) – Socket / Chipset: AM5 / AMD B840 – Compatible CPUs: AMD Ryzen 9000, 8000, 7000 series – Memory: 4× DDR5 DIMM, max 192 GB, up to 7600+ MT/s (OC), dual-channel, EXPO & AEMP – Storage: 2× M.2 PCIe 4.0 x4 + 1× M.2 PCIe 3.0 x4, 4× SATA 6 Gb/s – Expansion: 1× PCIe 4.0 x16 (CPU), 2× PCIe 3.0 x16 (x1 mode, chipset) – Rear USB: 2× USB 10Gbps Type-A, 1× USB 5Gbps Type-C, 4× USB 2.0 Type-A – Display: 2× DisplayPort 1.4 (8K@30Hz), 1× HDMI 2.1 (4K@60Hz) – Network: Realtek 2.5 Gb Ethernet – Audio: Realtek 7.1 HD, 24-bit/192 kHz – BIOS: 256 Mb Flash ROM, UEFI AMI – OS Support: Windows 11, Windows 10 64-bit – Warranty: 3 Years