ASUS Prime series motherboards are expertly engineered to unleash the full potential of AMD Ryzen™ 9000 series processors. The PRIME B840M-A-CSM motherboard provides users and PC DIY builders with a range of performance optimizations via intuitive software and firmware features. It’s designed to be Advanced AI PC-ready, offering the power and connectivity needed for demanding AI applications.

Digital Power Design

PRIME B840M-A-CSM features an 8+2+1 phase power design with discrete MOSFETs, ensuring efficient and stable power delivery for AMD processors plus steady performance for day-to-day use.

Three M.2 slots (up to 64 Gbps)

PRIME B840M-A-CSM offers a total of three M.2 slots, including two that support data-transfer speeds of up to 64 Gbps via PCIe 4.0, and one that supports PCIe 3.0. This enables quicker boot-up and app load times with OS or application drives.

SPECIFICATIONS

• CPU
  • AMD Socket AM5 for AMD Ryzen™ 9000 & 8000 & 7000 Series Desktop Processors*
  • * Refer to ASUS Support for CPU support list.
• Chipset: AMD B840 Chipset
• Memory
  • 4 x DDR5 DIMM slots
  • Max. 256GB
  • Supports up to 7600+MT/s (OC) with Ryzen™ 9000 & 8000 & 7000 Series Processors, ECC and Non-ECC, Un-buffered DIMM*
  • Dual channel memory architecture
  • Supports AMD Extended Profiles for Overclocking (EXPO™)
  • ASUS Enhanced Memory Profile (AEMP)
  • * Supported memory types, data rate (speed), and number of DRAM modules vary depending on the CPU and memory configuration, for more information please refer to the latest ASUS Support list.
  • * Non-ECC, un-buffered DDR5 memory supports On-Die ECC function.
• Graphics
  • 2 x DisplayPort**
  • 1 x HDMI™ port***
  • * Graphics specifications may vary between CPU types. Please refer to AMD CPU specifications.
  • ** Supports max. 8K@30Hz as specified in DisplayPort 1.4.
  • *** Supports 4K@60Hz as specified in HDMI 2.1.
• Expansion Slots
  • AMD Ryzen™ 9000 & 7000 Series Desktop Processors*
    • 1 x PCIe 4.0 x16 slot (supports x16 mode)
  • AMD Ryzen™ 8000 Series Desktop Processors
    • 1 x PCIe 4.0 x16 slot (supports x8/x4 mode)**
  • AMD B840 Chipset
    • 2 x PCIe 3.0 x16 slots (support x1 mode)
  • * Please check the PCIe bifurcation table on the support site (ASUS Support).
  • ** Specifications vary by CPU types.
  • To ensure compatibility of the device installed, please refer to ASUS Support for the list of supported peripherals.
• Storage
  • Total supports 3 x M.2 slots and 4 x SATA 6Gb/s ports
  • AMD Ryzen™ 9000 & 7000 Series Desktop Processors
    • M.2_1 slot (Key M), type 2280 (supports PCIe 4.0 x4 mode)
    • M.2_2 slot (Key M), type 2242/2260/2280 (supports PCIe 4.0 x4 mode)
  • AMD Ryzen™  8000 Series Desktop Processors
    • M.2_1 slot (Key M), type 2280 (supports PCIe 4.0 x4 mode)
    • M.2_2 slot (Key M), type 2242/2260/2280 (supports PCIe 4.0 x4/x2 mode)*
  • AMD B840 Chipset
    • M.2_3 slot (Key M), type 2280 (supports PCIe 3.0 x4 mode)
    • 4 x SATA 6Gb/s ports
  • * Specifications vary by CPU types.
  • AMD RAIDXpert2 Technology
  • Ryzen™ 9000 Series Processors: RAID 0/1/5/10
  • Ryzen™ 8000 Series Processors: RAID 0/1
  • Ryzen™ 7000 Series Processors: RAID 0/1/10
• Ethernet: 1x Realtek 2.5Gb Ethernet (ASUS LANGuard)
• USB
  • Rear USB (Total 7 ports)
    • 2 x USB 10Gbps ports (2 x Type-A)
    • 1 x USB 5Gbps port (1 x USB Type-C®)
    • 4 x USB 2.0 ports (4 x Type-A)
  • Front USB (Total 7 ports)
    • 1 x USB 5Gbps connector (supports USB Type-C®)
    • 1 x USB 5Gbps header supports 2 additional USB 5Gbps ports
    • 2 x USB 2.0 headers support 4 additional USB 2.0 ports
  • * USB Type-C® power delivery output: max. 5V/3A
• Audio: Realtek 7.1 Surround Sound High Definition Audio CODEC
• Form Factor: micro-ATX (24.4 x 24.4 cm)
• Warranty: 36 Months

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