ASUS Prime B840M-A-CSM M-ATX Motherboard

The ASUS Prime B840M-A-CSM is a Micro-ATX motherboard built around the AMD B840 chipset and the AM5 socket, designed to support AMD Ryzen 9000, Ryzen 8000, and Ryzen 7000 series desktop processors. It targets PC builders who need a compact, reliable foundation for a DDR5-based platform without sacrificing key connectivity or expandability. Power delivery is handled by an 8+2+1 phase digital power design using discrete MOSFETs, which helps ensure stable voltage regulation for the CPU under sustained workloads. The board carries the ASUS designation as Advanced AI PC-ready, reflecting its positioning for demanding compute tasks alongside everyday productivity use. Memory support is exclusively DDR5 in dual-channel configuration, with speeds rated up to 7600+ MT/s. The board supports both AMD EXPO (Extended Profiles for Overclocking) and ASUS AEMP (ASUS Enhanced Memory Profile), giving builders flexibility whether they use value DDR5 kits or higher-speed modules. Maximum supported capacity is 256 GB across the available DIMM slots. Both ECC and non-ECC unbuffered DDR5 memory are supported, and non-ECC DDR5 additionally benefits from die ECC functionality at the module level. Storage is well-served by three Key-M M.2 slots: two operating at PCIe 4.0 with transfer speeds up to 64 Gbps each, and one at PCIe 3.0. Four SATA 6 Gb/s ports provide additional drive connectivity for legacy or bulk storage. Expansion follows the B840 chipset's capabilities. For Ryzen 9000 and 7000 processors, the primary PCIe 4.0 x16 slot operates in full x16 mode. Ryzen 8000 series CPUs run that same slot at x8 or x4 mode. The B840 chipset contributes two additional PCIe 3.0 x16 mechanical slots, each operating at x1 electrical bandwidth. The rear I/O panel includes 2x USB 10 Gbps Type-A ports, 1x USB 5 Gbps Type-C port, 4x USB 2.0 Type-A ports, 2x DisplayPort outputs, 1x HDMI port, a Realtek 2.5 Gb Ethernet jack, 3x audio jacks, and a BIOS FlashBack button for firmware updates without a CPU or memory installed. Internal headers add a USB 5 Gbps Type-C connector, two USB 5 Gbps headers (supporting 4 additional ports total), two USB 2.0 headers (supporting 4 additional ports), and three Addressable Gen 2 (ARGB) headers for lighting accessories. Verifiable Specifications: - Socket: AM5 - Chipset: AMD B840 - Form Factor: Micro-ATX - CPU Compatibility: AMD Ryzen 9000, 8000, 7000 series desktop - Memory Type: DDR5, Dual Channel, Unbuffered (ECC and non-ECC) - Max Memory: 256 GB - Memory Speed: Up to 7600+ MT/s (with EXPO / AEMP) - M.2 Slots: 3x Key-M (2x PCIe 4.0 up to 64 Gbps; 1x PCIe 3.0) - SATA Ports: 4x SATA 6 Gb/s - Primary PCIe Slot: 1x PCIe 4.0 x16 (x16 mode with Ryzen 9000/7000; x8/x4 with Ryzen 8000) - Rear USB: 2x USB 10 Gbps Type-A; 1x USB 5 Gbps Type-C; 4x USB 2.0 Type-A - Display Output: 2x DisplayPort, 1x HDMI - Ethernet: Realtek 2.5 Gb - Power Phases: 8+2+1 digital with discrete MOSFETs - ARGB Headers: 3x Addressable Gen 2 - Warranty: 3 years - Price: ₹17,280 (IN)