ASUS PRIME B450M-A Motherboard

Package Contents

Please check your motherboard package for the following items:

If any of the above items are damaged or missing, please contact your retailer.

PRIME B450M-A Specifications

AMD B450 Chipset Features

• 4 x SATA 6.0 Gb/s ports, supporting RAID 0, RAID 1, and RAID 10
• 2 x SATA 6.0 Gb/s ports, supporting RAID 0, RAID 1, and RAID 10
• 1 x M.2 Socket 3, with M key, type 2242/2260/2280/22110 storage devices support (both SATA & PCIe 3.0 x4 modes)
• *The M.2 socket shares bandwidth with the SATA_5/6 ports. Therefore, the SATA_5/6 ports will be disabled when an M.2 device is installed.

Audio

Realtek® ALC 887-VD2 8-Channel High Definition Audio CODEC

• Illuminated Audio Pathway: Brighten your build with a glowing pathway!
• Audio Shielding: Ensures separation of analog/digital signals, greatly reducing multi-lateral interference.
• Dedicated Audio PCB Layers: Separate layers for left and right channels to safeguard the quality of sensitive audio signals.
• Premium Japanese Audio Capacitors: Provide warm, natural, and immersive sound with exceptional clarity and fidelity.
• Jack-detection and Front panel jack-swapping support
• *Use a chassis with an HD audio module in the front panel to support 8-channel audio output.

USB

• 4 x USB 3.1 Gen 1 port(s) (4 port(s) on the back panel)
• AMD B450 Chipset: 2 x USB 3.1 Gen 2 port(s) (2 port(s) on the back panel)
• 2 x USB 3.1 port(s) (Gen 1) (2 port(s) on the mid-board)
• 4 x USB 2.0 port(s) (4 port(s) on the mid-board)

ASUS 5X PROTECTION III

• SafeSlot Core: ASUS-exclusive SafeSlot provides reinforced PCIe connectivity to prevent damage.
• ASUS ESD Guards: Advanced USB protection.
• ASUS Overcurrent Protection: World-class circuit design prevents overcurrent and short-circuit damage.
• ASUS Stainless-Steel I/O: Corrosion-resistant stainless-steel I/O-shielding for 3x longer lasting durability!
• ASUS DIGI+ VRM: 6-phase digital power design.

Superb Performance

UEFI BIOS

• Advanced options with fast response time
• Easy DIY PC: Safe motherboard installation.
• Component-free areas to minimize risk of damage.
• Q-Design: ASUS Q-DIMM, ASUS Q-Slot.
• UEFI BIOS EZ Mode: User-friendly graphical interface.
• ASUS CrashFree BIOS 3
• ASUS EZ Flash 3

Summary of Specifications

AMD B450 Chipset

• 4 x SATA 6.0 Gb/s connectors with support for RAID 0, RAID 1, and RAID 10
• 2 x SATA 6.0 Gb/s connectors with support for RAID 0, RAID 1, and RAID 10
• 1 x M.2 Socket 3 with M key, type 2242/2260/2280/22110 (PCIe 3.0 & SATA modes) storage devices support.
• *The M.2 socket shares bandwidth with SATA_5/6 ports. Therefore, SATA_5/6 ports cannot be used when an M.2 device is installed.

Realtek® ALC 887-VD2 8-Channel High Definition Audio Codec

• Illuminated Audio Pathway: Brighten your build with a glowing pathway!
• Audio Shielding: Ensures separation of analog/digital signals, greatly reducing multi-lateral interference.
• Dedicated Audio PCB Layers: Separate layers for left and right channels to safeguard the quality of sensitive audio signals.
• Premium Japanese Audio Capacitors: Provide warm, natural, and immersive sound with exceptional clarity and fidelity.
• Support for jack-detection and front panel jack-swapping
• *Use a chassis with an HD audio module in the front panel to support 8-channel audio output.

USB Ports

• 4 x USB 3.1 Gen 1 port(s) (4 port(s) on the back panel)
• AMD B450 Chipset: 2 x USB 3.1 Gen 2 port(s) (2 port(s) on the back panel)
• 2 x USB 3.1 port(s) (Gen 1) (2 port(s) on the mid-board)
• 4 x USB 2.0 port(s) (4 port(s) on the mid-board)

ASUS 5X PROTECTION III

• SafeSlot Core: ASUS-exclusive SafeSlot provides reinforced PCIe connectivity to prevent damage.
• ASUS ESD Guards: Advanced USB protection.
• ASUS Overcurrent Protection: World-class circuit design prevents overcurrent and short-circuit damage.
• ASUS Stainless-Steel I/O: Corrosion-resistant stainless-steel I/O-shielding for 3x longer lasting durability!
• ASUS DIGI+ VRM: 6-phase digital power design.

Superb Performance

UEFI BIOS

• Cooling Design: Stylish fanless design: heatsink solution + ASUS Fan Xpert 2.
• 1 x PS/2 Keyboard port (Purple)
• 1 x PS/2 Mouse port (Green)
• 1 x HDMI port
• 1 x DVI-D port
• 1 x LAN (RJ-45) port
• 2 x USB 3.1 Gen 2 port(s)
• 4 x USB 3.1 Gen 1 port(s)
• 3 x Audio jacks supporting 8-Channel Audio
• 1 x USB 3.1 Gen 1 connector supporting 2 additional USB 3.1 Gen 1 ports
• 2 x USB 2.0 connectors supporting 4 additional USB 2.0/1.1 ports
• 1 x M.2 Socket 3 for M key, type 2242/2260/2280/22110 devices (both SATA & PCIe modes) support
• 6 x SATA 6.0Gb/s connectors
• 1 x COM connector
• 1 x TPM connector
• 1 x CPU Fan connector
• 1 x Aura RGB Strip header
• 2 x Chassis Fan connectors (supports DC and PWM modes)
• 1 x Front Panel Audio connector
• 1 x EATX Power connector (24-pin)
• 1 x EATX 12V Power connector (8-pin)
• 1 x Clear CMOS header (2-pin)
• 1 x S/PDIF out header
• 1 x Speaker connector
• 1 x System Panel connector
• 128 Mb Flash ROM, UEFI AMI BIOS, PnP, SM BIOS 3.1, ACPI 6.1, Multi-language BIOS, ASUS 3. F3 My Favorites, Last Modified Log, F12 User PrintScreen, ASUS SPOUS PrintScreen, ASUS EZ Flash 3, ASUS CrashFree
• WOL by PME, PXE
• Drivers
• ASUS Utilities
• Anti-Virus Software (OEM version)
• Windows® 10 64-bit / 8 64-bit
• Form Factor: uATX, 9.6inch x 9.5inch (24.4cm x 24.0cm)
• Specifications are subject to change without notice.

Product Introduction

Before Proceeding

Before installing motherboard components or changing motherboard settings, please pay attention to the following precautions.

• Static Electricity: To prevent damage from static electricity, ground yourself before touching any components. Ensure all cables are disconnected from the motherboard before installation or removal.
• Handling: Handle components with care to avoid damage.
• Installation: Follow the installation instructions carefully.

Motherboard Layout

A diagram showing the motherboard layout with numbered components.

• 1. CPU Socket
• 2. DIMM Slots
• 3. ATX Power Connectors
• 4. CPU Fan Connector
• 5. Chassis Fan Connectors
• 6. M.2 Socket 3
• 7. SATA Connectors
• 8. Front Panel Audio Connector
• 9. USB Connectors
• 10. PCIe Slots
• 11. Chipset
• 12. CMOS Battery
• 13. BIOS ROM
• 14. Front Panel Connectors
• 15. COM Connector
• 16. TPM Connector
• 17. S/PDIF Out Header
• 18. Speaker Connector

1. Power Connectors

ATX Power Connectors (24-pin EATXPWR, 8-pin EATX12V)

These connectors are for ATX power supply plugs. The power supply plugs are designed to fit into these connectors in only one direction. Find the correct orientation and push firmly until the connectors are fully seated.

• We recommend using an ATX 12V Specification 2.0 compliant power supply.
• A power supply unit (PSU) with a minimum wattage of 350W is recommended. This type of PSU has both 24-pin and 8-pin power plugs.
• Do not forget to connect the 8-pin EATX +12V power plug. Otherwise, the system will not boot.
• We recommend using a PSU with a higher wattage output when configuring a system with more power-consuming devices or when planning to install additional devices. Insufficient power may cause system instability or failure to boot.
• If you are unsure about the minimum power supply required for your system, refer to the recommended power supply wattage calculator at http://support.asus.com.cn/PowerSupply.aspx?SLanguage=en.

CPU and Chassis Fan Connectors (4-pin CPU_FAN, 4-pin CHA_FAN)

Connect the fan cables to the fan connectors on the motherboard, ensuring that the black wire of each cable matches the ground pin of the connector.

• Do not forget to connect the fan cables to the fan connectors. Insufficient airflow inside the system may damage motherboard components. These are not jumpers! Do not place jumper caps on the fan connectors!
• The CPU_FAN connector supports a CPU fan with a maximum fan power of 1A (12W).

M.2 Socket 3

This socket allows you to install M.2 SSD modules (NGFF).

• The M.2 socket supports M key, type 2242/2260/2280/22110 storage devices in both PCIe 3.0 x4 and SATA modes.
• The M.2 socket shares bandwidth with the SATA_5/6 ports, so SATA_5/6 ports cannot be used when an M.2 device is installed.

AMD AM4 CPU Socket

This motherboard features an AMD AM4 socket designed for AMD Ryzen™ 2nd Generation / Ryzen™ with Radeon™ Vega Graphics / Ryzen™ 1st Generation processors.

For more details, refer to the CPU section.

RGB Header (4-pin RGB_HEADER & 5050 RGB_HEADER)

This connector supports multiple chassis-installed functions. Connect RGB LED strips of a single color (RGB) to this header. Maximum power (12V) of 3A and 3 meters is not exceeded.

If your LED strip does not light up, check if the internal RGB LED cable and the RGB LED strip are connected in the correct direction, and the 12V connector is aligned with the 12V header on the motherboard.

• The LED strip will only light up when the system is running.
• LED strips are purchased separately.

DDR4 DIMM Slots

Install DDR4 DIMM memory modules of 2GB, 4GB, 8GB, and 16GB without buffer in these DIMM sockets.

For more details, refer to System Memory.

SATA 6.0 Gb/s Connectors (7-pin SATA6G)

These connectors connect to Serial ATA hard disk drives via the Serial ATA 6.0 Gb/s signal cable.

RTC CMOS Clear (2-pin CLRTC)

This header allows you to clear the RTC CMOS data. System startup information such as date, time, and system passwords.

To clear RTC CMOS:

1. Turn off the computer and unplug the power cord.
2. Use a metal object, such as a screwdriver, to short these two pins.
3. Plug in the power cord and turn on the computer.
4. Hold down the key during the boot process and enter BIOS Setup to re-enter data.

If the above steps do not help, remove the onboard battery and short the two pins again. Reinstall the battery after clearing the RTC CMOS data.

Speaker Connector (10)

This 4-pin connector is for the system warning speaker installed on the chassis. This speaker allows you to hear system beeps and warnings.

USB 3.1 Gen 1 Connector (10) (12)

Connect a USB 3.1 Gen 1 module for the front or rear panel ports. This connector complies with USB 3.1 Gen 1 specifications and provides faster data transfer speeds up to 5Gb/s.

USB 2.0 Connectors (10)

These connectors are for USB 2.0 ports. This interface supports the System Management Platform.

COM Connector (10) (12)

This connector is for a serial port.

Front Panel Audio Connector (10)

This connector is for a front panel audio input/output module on the chassis that supports the HD Audio standard. Connect one end of the front panel audio input/output module cable to this connector.

S/PDIF Out Header (10)

This connector is for an additional digital audio (S/PDIF) output port. Connect the S/PDIF Out module. Connect the cable to this connector, then install the module in an expansion slot that opens at the back of the system chassis.

PCI Express 2.0 x1 Slots (17)

This motherboard features two PCI Express 2.0 x1 slots that support PCI Express 2.0 x1 network cards, SCSI cards, and other cards that comply with PCI Express specifications.

PCI Express 3.0/2.0 x16 Slot (19)

This motherboard features a PCI Express 3.0/2.0 x16 slot that supports PCI Express 3.0 x16 graphics cards that comply with PCI Express specifications.

Back Panel Connectors

1. PS/2 Mouse Port (Green): Connects to a PS/2 mouse.
2. VGA Video Adapter Port: This 15-pin port is for VGA monitors and other VGA-compatible devices.
3. USB 3.1 Gen 1 Ports (up to 5Gbps): These 9-pin Universal Serial Bus (USB) ports connect to USB 3.1 Gen 1 devices.
4. USB 3.1 Gen 2 Ports (up to 10Gbps) (Greenish Blue, Type-A): These 9-pin Universal Serial Bus (USB 3.1) ports are for USB 3.1 Gen 2 devices.
5. LAN (RJ-45) Port: This port provides Gigabit Ethernet connectivity to a local area network (LAN). For LED indicators, refer to the LAN port table below.
6. Audio Jacks (Green, Light Blue, Pink): Connect speakers, headphones, or a microphone.
7. DVI-D Port: Digital Visual Interface port.
8. HDMI Port: High-Definition Multimedia Interface port.

LAN Port LED Indicators

USB Port Usage Notes

• USB 3.1 Gen 2 / Gen 1 devices are only usable for data storage.
• Due to the design of AMD's AM4 chipsets, all USB devices are controlled by the xHCI controller, including USB 2.0 and USB 3.1 Gen 2 / Gen 1 ports.
• We recommend connecting USB 3.1 Gen 2 devices to USB 3.1 Gen 2 ports for faster and better performance of your USB 3.1 Gen 2 devices.

CPU

AMD AM4 CPU Socket

This motherboard features an AMD AM4 socket designed for AMD Ryzen™ 2nd Generation / Ryzen™ with Radeon™ Vega Graphics / Ryzen™ 1st Generation processors.

Before installing the CPU, unplug all power cables from the power outlet.

The AM4 socket has a different pinout from the FM2+/FM2 socket. Ensure that you are using a CPU designed for the AM4 socket. The CPU only fits into the socket in one correct orientation. Do not force the CPU into the socket to avoid bending the pins and damaging the CPU!

Installing the CPU

Diagrams illustrating CPU installation steps.

Installing the CPU Heatsink and Fan Assembly

Diagrams illustrating heatsink and fan installation.

System Memory

DDR4 DIMM Slots

This motherboard features four Double Data Rate 4 (DDR4) Dual Inline Memory Module (DIMM) sockets. The figure shows the location of the DDR4 DIMM sockets.

*You can install different memory sizes in Channel A and Channel B. The system maps the smaller memory size in a channel for dual-channel configuration. Any additional memory in the channel with the larger size is mapped for single-channel operation.

Install DIMMs with the same CAS Latency. For optimal compatibility, we recommend installing memory modules of the same revision with the same date code (D/C) from the same vendor. Consult your retailer for the correct memory modules.

For system stability, use a more efficient memory cooling system to support full memory load (4 DIMMs).

Refer to www.asus.com for the latest Memory QVL (Qualified Vendors List).

Recommended Memory Configurations

Diagrams showing recommended DIMM installation for dual-channel configurations.

Installing DIMMs

Diagrams illustrating the process of installing DIMMs into the slots.

BIOS Setup Utility

Use the BIOS Setup utility to update the BIOS or configure its parameters. The BIOS screens include navigation keys and brief online help to guide you in using the BIOS setup utility.

Entering BIOS Setup

To enter BIOS Setup during startup:

Press or during Power-On Self-Test (POST). If you do not press or , POST continues its routine.

To enter BIOS Setup after POST:

Press ++ simultaneously.

Press the Reset button on the system chassis.

Press the power button to turn off the system and then turn it back on. Perform this option only if you did not enter BIOS Setup using the first two options.

Forcing a reset from a running operating system using the power button, reset button, or ++ keys can damage your data or system. We recommend always shutting down the system properly from the operating system.

The BIOS setup screens shown in this section are for reference purposes only and may not exactly match what you see on your screen. Download the latest BIOS file for this motherboard from the ASUS website at www.asus.com.

If the system becomes unstable after changing BIOS settings, load the default settings to ensure system compatibility and stability. Select Load Optimized Defaults from the Exit menu or press the F5 shortcut key.

If the system does not boot after changing BIOS settings, try clearing the CMOS and resetting the motherboard to its default values. Refer to the Motherboard Layout section for information on how to clear the RTC CMOS.

BIOS Menu Screen

The BIOS Setup utility can be used in two modes: EZ Mode and Advanced Mode. To switch between the two modes, press .

EZ Mode

By default, the EZ Mode screen appears when you enter the BIOS Setup utility. EZ Mode provides an overview of basic system information and allows you to select the display language, system performance mode, fan profile, and boot device priority.

Click Advanced Mode () or press to access Advanced Mode.

The default screen for entering the BIOS setup utility can be changed. Refer to the Setup Mode item under the Boot menu for more details.

• System Information: Displays the selected system mode.
• D.O.C.P.: Disabled/Enabled.
• Fan Profile: Displays CPU and Chassis fan speeds.
• CPU Temperature: Displays CPU temperature.
• VDDCR CPU Voltage: Displays CPU voltage.
• Motherboard Temperature: Displays motherboard temperature.
• SATA Information: Displays SATA port status.
• M.2 Information: Displays M.2 slot status.
• Q-Fan Control: Allows control of fan speeds.
• Boot Priority: Choose one and drag the items.
• Search FAQ: Search for answers to frequently asked questions.
• AURA ON/OFF: Enable or disable Aura lighting.
• EZ System Tuning: Select an icon to apply a pre-configured profile for improved system performance or energy savings. Options include: Normal, Performance, Power Saving, Energy Saving.

Advanced Mode

Advanced Mode provides advanced options for experienced users to configure BIOS settings. The figure below shows an example of Advanced Mode. Refer to the following sections for detailed settings.

• My Favorites: Displays your favorite BIOS settings.
• Main: Displays basic system information.
• AI Tweaker: Allows overclocking and performance tuning.
• Advanced: Configures advanced system settings.
• Monitor: Displays system hardware monitoring information.
• Boot: Configures boot settings.
• Tool: Provides access to various utility tools.
• Exit: Allows you to save or discard changes and exit BIOS Setup.

Exit Menu

The Exit menu items allow you to load optimized default values for the QR items, and save or discard your changes to the BIOS items.

• Load Optimized Defaults: This option allows you to load the default values for each of the parameters in the Setup menus. When you select this option or press F5>, a confirmation window appears. Select OK to load the default values.
• Save Changes & Reset: When you have finished making your selections, select this option from the Exit menu to ensure that your selected values are saved. When you select this option or press F10>, a confirmation window appears. Select OK to save changes and exit.
• Discard Changes & Exit: This option allows you to exit the Setup utility without saving changes. Selecting this option or pressing Esc> will bring up a confirmation window. Select OK to discard changes and exit.
• Launch EFI Shell from USB drives: This option allows you to launch the EFI Shell (shell:lif) program from one of the available USB devices.