ASUS PRIME B840M-A-CSM AMD B840 Socket AM5 Micro ATX 90MB1J10-M0EAYC

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.

ASUS Corporate Stable Model
ASUS Corporate Stable Model (CSM) is a commercial program designed to provide stable and reliable motherboards. Offering up to 36-month product lifecycle support and 6-month end-of-life notice to allow sufficient lead times for your organization to get ready for product transitions. Each purchase of an ASUS CSM motherboard comes with ASUS Control Center Express - server-grade IT management software.

ASUS Control Center Express
ASUS Control Center Express is an integrated IT monitoring and management software designed to deploy faster, simplify IT operations and improve productivity with comprehensive control and user-friendly functions. ASUS Control Center Express is compatible with over 100 ASUS motherboards to provide a high-quality, TCO-optimized solution for your business needs.

Optimize IT endpoint management
Designed to assist IT staff in monitoring and controlling devices within their corporate networks, and facilitate inventory checking in multiple locations remotely.

Automate IT maintenance
Allows IT staff to schedule automatic updates of the latest BIOS, software and utilities to specific or all devices at off-peak times, enhancing system stability and IT operational flexibility.

Securely manage all of endpoints
Securely manage endpoint configuration, portable storage access and PC software applications by enabling them to create grouping rules on individual devices.

Performance
AI Solutions
ASUS AI Solutions include AI Advisor as your technical expert with expertise in PC performance.

AI Advisor
ASUS AI Advisor allows users to explore the functionality and advanced features of ASUS motherboards in a simple and straightforward way.7

Performance
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.5

The multi-layered printed circuit board design quickly dissipates heat around the voltage regulators to improve overall system stability and provide the CPU with more overclocking headroom.

The Power Saving function contains several settings to easily optimize power consumption and maximize energy savings. You can enable a CPU power limit, darken Aura lighting and set the fan profile to a Power Saving mode. You can also toggle the Power Saver plan that is built into Microsoft Windows.

The Digi+ voltage-regulator module (VRM) delivers real-time control over voltage droop, automatically switching frequency and power-efficiency settings.

Enhanced Memory & Storage Performance
Enhanced DDR5 performance
Comprehensive memory tuning options are the cornerstone of PRIME motherboards. The PRIME B840M-A-CSM maximizes the potential of your DDR5 modules, from entry-level to extreme-speed kits.2
For entry-level modules without EXPO- support, ASUS Enhanced Memory Profile (AEMP) automatically detects memory chips and provides optimized profiles for enhanced performance.
For those looking to surpass stock DDR5 speeds, the PRIME B840M-A-CSM offers extensive AMD Extended Profiles for Overclocking (EXPO-) support and a wide array of UEFI settings for further performance tweaks.3

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.4

Cooling
Cooler by design
The PRIME B840M-A-CSM motherboard is engineered with multiple onboard heatsinks and an array of hybrid fan headers to help ensure your rig stays cool and stable under intense workloads.

Smart Cooling precision

ASUS Fan Xpert 2+
ASUS Fan Xpert 2+ software provides comprehensive control over fans. An Auto-Tuning mode intelligently configures all parameters with a single click. There-s also an Extreme Quiet mode that reduces chassis fan speeds to below the default minimum to keep your system whisper-quiet when performing light tasks. Fans can also be controlled via the UEFI BIOS.5

Cooler compatibility
ASUS AIO coolers offer robust performance, high overclocking potential, bold aesthetics and customizable functionality for new motherboards, empowering you to build your dream gaming rig.5

Flexibility
Empowering connections
This motherboard offers a versatile range of connectivity, including support for PCIe 4.0 slot and an arsenal of USB ports which includes Type-C- connections.

Realtek 2.5 Gb Ethernet
Realtek 2.5 Gb Ethernet reduces CPU overhead and offers exceptionally high TCP and UDP throughput for faster, smoother data transfers.

Front USB 5Gbps Type-C-
This motherboard features a USB 5Gbps Type-C- front panel connector for speedy data transfers of up to 5Gbps.5

Customization
Personalization
The PRIME B840M-A-CSM enhances the user experience across the board, from simplifying BIOS setting adjustments to offering customizable RGB lighting controls for a uniquely personal system aesthetic.

UEFI BIOS
The UEFI interface delivers easy-to-use configuration options for PC beginners, and advanced features for veterans.

ASUS DriverHub
Simplify driver management with automatic detection, one-click installation and update for smooth, efficient system performance.

Armoury Crate
Customize Aura Sync RGB and control ASUS devices. Includes product registration and updates.

Aura Sync
Complete RGB lighting control for enthusiast systems, ensuring seamless synchronization with compatible hardware.

Addressable Gen 2 RGB headers
Three addressable Gen 2 headers detect LED counts on compatible RGB devices, automatically adjusting lighting effects accordingly.

Customization
DIY friendly
The PRIME B840M-A-CSM motherboard features EZ PC DIY innovations that simplify and speed up the PC building process, making DIY easy and convenient.

Pre-mounted I/O shield
Our pre-installed I/O shield safeguards ports, simplifies the build process, increases functionality and enhances aesthetics for PC DIY enthusiasts.

BIOS FlashBack-
BIOS FlashBack- simplifies BIOS updates. Just load the BIOS file onto a FAT32 USB stick, insert it into the BIOS FlashBack- port, and press a button - no CPU or memory needed.

SafeSlot Core+
SafeSlot Core+ is a one-piece stainless-steel brace that shields the slot to protect it from damage. The metal cover is tightly secured to the slot with hooks, and the entire assembly is firmly anchored to the PCB with strengthened solder points to provide a secure foundation for heavyweight graphics cards.

Q-LED Core
The Q-LED Core display produces color-coded lights during the Power-On Self-Test (POST) that can help you troubleshoot potential issues.

Build for the most advanced pc for gaming and creating
When only the fastest will do, ASUS motherboards deliver. With faster dual-channel DDR5 memory support, AMD EXPO- technology and PCIe- 4.0 support for both graphics and NVMe, you can play the most demanding games and deliver your biggest projects with the revolutionary performance of an ASUS motherboard and AMD Ryzen- 9000, 8000, and 7000 Series processors.

Specs




Processor


Processor manufacturer

The manufacturer that produced the processor.

AMD


Processor socket

Mechanical component(s) that provides mechanical and electrical connections between a microprocessor and a printed circuit board (PCB). This allows the processor to be replaced without soldering.

Socket AM5


Compatible processor series

A processor which is compatible with this device, belongs to a 'series' which is part of 'family' e.g Celeron D, Celeron G, Celeron M, or, in some cases, is the same as 'family'.

AMD Ryzen 7000 Series, AMD Ryzen 8000 Series, AMD Ryzen 9000 Series


Supported processor sockets

The sockets (plugs) for processors that are supported (can be used) by the device.

Socket AM5


Memory


Supported memory types

Types of memory which can be used with the product.

DDR5-SDRAM


Number of memory slots

4


Memory slots type

A memory slot, also known as a memory socket or RAM slot, is what allows computer memory (RAM) to be inserted into the computer. Depending on the motherboard, there will usually be 2 to 4 memory slots (sometimes more on high-end motherboards). The most common types of RAM are SDRAM and DDR for desktop computers and SODIMM for laptop computers, each having various types and speeds.

DIMM


Memory channels

Dual-channel


ECC ?ompatibility

ECC & Non-ECC


Supported memory clock speed (max)

7600 MHz


Maximum internal memory

The maximum internal memory which is available in the product.
2 GB


Unbuffered memory




Storage controllers


Supported storage drive types

The type of storage drives the device is compatible with.

HDD & SSD


Supported storage drive interfaces

M.2, SATA III


Number of HDDs supported

The total number of hard drives that can be used in/with this product.

4


Number of storage drives supported

How many storage drives can be fit into the product at once.

7


RAID support

The device uses RAID, which is a storage technology that combines multiple disk drive components into a logical unit for the purposes of data redundancy and performance improvement. Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the specific level of redundancy and performance required.




RAID levels

RAID is a storage technology that combines multiple disk drive components into a logical unit for the purposes of data redundancy and performance improvement. Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the specific level of redundancy and performance required.

0, 1, 5, 10


Graphics


Parallel processing technology support

Parallel processing technology is the simultaneous use of more than one CPU or processor core to execute a program or multiple computational threads. Ideally, parallel processing makes programs run faster because there are more engines (CPUs or Cores) running it. In practice, it is often difficult to divide a program in such a way that separate CPUs or cores can execute different portions without interfering with each other. Most computers have just one CPU, but some models have several, and multi-core processor chips are becoming the norm. There are even computers with thousands of CPUs.

Not supported


Maximum resolution

The maximum number of pixels that can be displayed in the image. It is usually quoted as width - height,: for example, "1024 - 768" means the width is 1024 pixels and the height is 768 pixels.

7680 x 4320 pixels


Internal I/O


USB 2.0 connectors

The end of a cable with a USB 2.0 connector. USB 2.0 was released in April 2000 (now called "Hi-Speed"), adding higher maximum signaling rate of 480 Mbit/s (effective throughput up to 35 MB/s or 280 Mbit/s), in addition to the "USB 1.x Full Speed" signaling rate of 12 Mbit/s. USB 2.0 connectors are usually colored black.

2


USB 3.2 Gen 1 (3.1 Gen 1) connectors

This is a connector (normally attached to a cable) for USB 3.0. USB 3.0 is the second major revision of the Universal Serial Bus (USB) standard for computer connectivity. First introduced in 2008, USB 3.0 adds a new transfer mode called "SuperSpeed," (distinguishable from USB 2.0 by either the blue colour of the port or the initials SS) capable of transferring data at up to 5Gbit/s-more than ten times as fast as the 480 Mbit/s top speed of USB 2.0.

2


Number of SATA III connectors

Serial ATA (Advanced Technology Attachment) (SATA) is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives and optical drives. SATA III (revision 3.x) interface, formally known as SATA 6Gb/s, is a third generation SATA interface running at 6.0Gb/s. The bandwidth throughput, which is supported by the interface, is up to 600MB/s. This interface is backwards compatible with SATA 3 Gb/s interface.

4


S/PDIF out connector




Front panel audio connector




Front panel connector




ATX Power connector (24-pin)




CPU fan connector




Number of CPU fan connectors

2


Number of chassis fan connectors

2


EPS power connector (8-pin)




Number of EPS power connectors (8-pin)

1


Number of COM connectors

1


TPM connector




RGB LED pin header




Number of RGB LED pin headers

3


Rear panel I/O ports


USB 2.0 ports quantity

Number of USB 2.0 ports (connecting interfaces) in the device. USB 2.0 was released in April 2000 (now called "Hi-Speed"), adding higher maximum signaling rate of 480 Mbit/s (effective throughput up to 35 MB/s or 280 Mbit/s), USB 2.0 ports are usually black.

4


USB 3.2 Gen 1 (3.1 Gen 1) Type-C ports quantity

Number of USB 3.0 (3.1 Gen 1) ports with Type-C connector. USB 3.0 (3.1 Gen 1) is USB interface version which supports transfer rate up to 5 Gbit/s (SuperSpeed). USB Type-C connector has symmetrical design architecture and compatible with Thunderbolt 3 interface.

1


USB 3.2 Gen 2 (3.1 Gen 2) Type-A ports quantity

2


Ethernet LAN (RJ-45) ports

Number of Ethernet LAN (RJ-45) ports (connecting interfaces) in the device. Ethernet LAN (RJ-45) ports allow a computer to connect to the ethernet.

1



Rear panel I/O ports


HDMI ports quantity

The number of sockets (ports) for HDMI connections. HDMI (High-Definition Multimedia Interface) is a compact audio/video interface for transferring uncompressed video data and compressed/uncompressed digital audio data from a HDMI-compliant device ("the source device") to a compatible computer monitor, video projector, digital television, or digital audio device. HDMI is a digital replacement for existing analog video standards.

1


HDMI version

2.1


DisplayPorts quantity

Number of DisplayPorts. A DisplayPort is a digital display interface developed by the Video Electronics Standards Association (VESA). The interface is primarily used to connect a video source to a display device such as a computer monitor, though it can also be used to carry audio, USB, and other forms of data.

1


DisplayPort version

1.4


Headphone outputs

Number of sockets /ports where headphones are connected.

1


Line-in




Network


Ethernet LAN

An Ethernet LAN (Local Area Network) interface is present, for a wired conection via a cable.




Ethernet interface type

2.5 Gigabit Ethernet


Wi-Fi

Popular technology that allows an electronic device to exchange data or connect to the internet wirelessly using radio waves.




Features


Motherboard chipset

The chipset connects the microprocessor to the rest of the motherboard.

AMD B840


Audio output channels

An audio output channel is an electric circuit which acts as a path for a signal produced by a device. A device may have several audio output channels.

7.1 channels


Product colour

The colour e.g. red, blue, green, black, white.

Grey


Component for

What this product is used as a part of (component for).

PC


Motherboard form factor

Design of the motherboard (ATX, BTX etc).

micro ATX


Motherboard chipset family

The category of motherboard chipset e.g. Intel, AMD.

AMD


Power source type

What the power source is.

ATX


Windows operating systems supported

Windows vesions wich can be used with the device.

Windows 10 x64, Windows 11


Expansion slots


PCI Express x16 (Gen 3.x) slots

Places where PCI Express x16 (Gen 3.x) are placed inside and connected to the computer motherboard.

2


PCI Express x16 (Gen 4.x) slots

1


Number of M.2 (M) slots

3


1st M.2 largest key size

2280


1st M.2 highest PCI Express generation

4.0


2nd M.2 largest key size

2280


2nd M.2 highest PCI Express generation

4.0


3rd M.2 largest key size

2280


3rd M.2 highest PCI Express generation

3.0


BIOS


BIOS type

The BIOS (Basic Input/Output System) initializes and tests system hardware components, and loads a bootloader or an operating system from a mass memory device. The BIOS additionally provides abstraction layer for the hardware, i.e. a consistent way for application programs and operating systems to interact with the keyboard, display, and other input/output devices. There are several types of BIOS, including the motherboard ROM BIOS, video BIOS, drive controller BIOS, network adapter BIOS, and SCSI adapter BIOS.

UEFI AMI


BIOS memory size

256 Mbit


Packaging data


Package width

The distance from one side of the packaging to the other.

275 mm


Package depth

The distance from the front to the back of the packaging.

275 mm


Package height

The distance from the top to the bottom of the packaging.

67.5 mm


Package weight

Weight of the packaged product.

1.45 kg


Weight & dimensions


Width

The measurement or extent of something from side to side.

244 mm


Depth

The distance from the front to the back of something.

244 mm


Packaging content


Cables included

SATA


Screws included




Other features


Weight

Weight of the product without packaging (net weight). If possible, the net weight is given including standard accessories and supplies. Please note that sometimes the manufacturer leaves out the weight of accessories and/or supplies.

910 g


Quick installation guide