ASUS PRIME B840M-A-CSM AMD B840 DDR5 Motherboard
Overview
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.
Specifications
CPU
AMD Socket AM5 for AMD Ryzen™ 9000 & 8000 & 7000 Series Desktop Processors*
* Refer to https://www.asus.com/support/download-center/ for CPU support list.
Chipset
AMD B840 Chipset
Memory
4 x DIMM slots, max. 192GB, DDR5
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 CPU/Memory Support list under the Support tab of product information site or visit https://www.asus.com/support/download-center/. Adjustments will be made based on the specifications of mass-produced memory products available on the market.
* 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 (https://www.asus.com/support/FAQ/1037507/).
** Specifications vary by CPU types.
– To ensure compatibility of the device installed, please refer to https://www.asus.com/support/download-center/ 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
1 x 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*
– Supports: Jack-detection, Multi-streaming, Front Panel Jack-retasking
– Supports up to 24-Bit/192 kHz playback
Audio Features
– Audio Shielding
– Premium audio capacitors
– Dedicated audio PCB layers
* A chassis with an HD audio module in the front panel is required to support 7.1 Surround Sound audio output.
Back Panel I/O 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)
2 x DisplayPort
1 x HDMI™ port
1 x Realtek 2.5Gb Ethernet port
3 x Audio jacks
1 x BIOS FlashBack™ button
Internal I/O Connectors
Fan and Cooling Related
1 x 4-pin CPU Fan header
1 x 4-pin CPU OPT Fan header
2 x 4-pin Chassis Fan headers
Power Related
1 x 24-pin Main Power connector
1 x 8-pin 12V CPU Power connector
Storage Related
3 x M.2 slots (Key M)
4 x SATA 6Gb/s ports
USB
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
Miscellaneous
3 x Addressable Gen 2 headers
1 x Clear CMOS header
1 x COM Port header
1 x Front Panel Audio header (F_AUDIO)
1 x S/PDIF Out header
1 x SPI TPM header (14-1 pin)
1 x 10-1 pin Front Panel System header
Special Features
ASUS 5X PROTECTION III
– DIGI VRM
– LANGuard
– Overvoltage protection
– SafeSlot Core
– Stainless-steel back I/O
ASUS Q-Design
– Q-Dashboard
– Q-DIMM
– Q-LED Core
– Q-Slot
ASUS Thermal Solution
– M.2 heatsink
– VRM heatsink design
ASUS EZ DIY
– BIOS FlashBack™ button
– BIOS FlashBack™ LED
– Pre-mounted I/O shield
Aura Sync
– Addressable Gen 2 headers
Software Features
ASUS Exclusive Software
Armoury Crate
– Aura Creator
– Aura Sync
– Fan Xpert 2
– Power Saving
ASUS DriverHub
TurboV Core
ASUS CPU-Z
Adobe Creative Cloud (Free Trial)
Norton 360 Deluxe (60 Days Free Trial)
WinRAR (40 Days Free Trial)
UEFI BIOS
ASUS EZ DIY
– ASUS CrashFree BIOS 3
– ASUS EZ Flash 3
– ASUS UEFI BIOS EZ Mode
– ASUS MyHotkey
Remote Management Features
IT Management software supported
– ASUS Control Center Express (ACCE)
BIOS
256 Mb Flash ROM, UEFI AMI BIOS
Manageability
WOL by PME, PXE
Accessories
Cables
2 x SATA 6Gb/s cables
Miscellaneous
1 x M.2 rubber package
2 x Screw packages for M.2 SSD
Documentation
1 x ACC Express Activation Key Card
1 x Quick start guide
Operating System
Windows 11, Windows 10 64-bit
Form Factor
micro-ATX Form Factor
9.6 inch x 9.6 inch (24.4 cm x 24.4 cm)