ASUS PRIME B550M-A Motherboard

Safety Information

Please read the following safety precautions before installing the motherboard and components.

Electrical Safety

• To prevent electrical shock hazard, disconnect the power cable from the electrical outlet before relocating the system.
• When adding or removing devices, ensure power cables are unplugged before connecting signal cables. Disconnect all power cables before adding a device if possible.
• Before connecting or removing signal cables from the motherboard, ensure all power cables are unplugged.
• Seek professional assistance before using an adapter or extension cord, as these could interrupt the grounding circuit.
• Ensure your power supply is set to the correct voltage for your area. Contact your local power company if unsure.
• If the power supply is broken, do not attempt to fix it yourself. Contact a qualified service technician or your retailer.

Operation Safety

• Before installing the motherboard and adding components, carefully read all manuals included in the package.
• Before using the product, ensure all cables are correctly connected and power cables are not damaged. Contact your dealer immediately if any damage is detected.
• To avoid short circuits, keep paper clips, screws, and staples away from connectors, slots, sockets, and circuitry.
• Avoid dust, humidity, and temperature extremes. Do not place the product in areas exposed to moisture.
• Place the product on a stable surface.
• If you encounter technical problems, contact a qualified service technician or your retailer.
• Your motherboard should only be used in environments with ambient temperatures between 0°C and 40°C.

About This Guide

This user guide provides information for installing and configuring the motherboard. It is organized into chapters covering product introduction, BIOS and RAID support, and appendices.

Conventions Used:

• CAUTION: Information to prevent damage to components and injuries.
• IMPORTANT: Instructions that MUST be followed to complete a task.
• NOTE: Tips and additional information to help complete a task.

For additional information, refer to the ASUS website or optional documentation.

Package Contents

Verify that your motherboard package contains the following items:

• 1 x PRIME B550M-A motherboard
• 2 x SATA 6Gb/s cables
• 1 x I/O Shield
• 1 x M.2 SSD screw package
• 1 x Support DVD
• 1 x User manual

If any items are damaged or missing, contact your retailer.

PRIME B550M-A Specifications Summary

Chapter 1: Product Introduction

1.1 Before You Proceed

Take note of the following precautions before installing motherboard components or changing settings:

• Unplug the power cord from the wall socket before touching any component.
• Before handling components, use a grounded wrist strap or touch a grounded object (like the power supply case) to avoid static discharge damage.
• Ensure the ATX power supply is switched off or the power cord is detached before installing or removing components. Failure to do so may cause severe damage to the motherboard, peripherals, or components.

1.2 Motherboard Overview

The ASUS PRIME B550M-A is an AMD Socket AM4 motherboard designed for 3rd Gen AMD Ryzen™ Processors. It features a compact mATX form factor.

Motherboard Layout Description:

• 1. CPU Socket: AMD Socket AM4 for 3rd Gen AMD Ryzen™ Processors.
• 2. DDR4 DIMM Slots: Four Dual Inline Memory Module (DIMM) slots for DDR4 memory.
• 3. Expansion Slots: One PCIe x16 slot for graphics cards and two PCIe 3.0 x1 slots for other expansion cards.
• 4. Fan Headers: Headers for connecting system cooling fans (CPU Fan, CPU OPT Fan, Chassis Fan).
• 5. Power Connectors: Connectors for the ATX power supply (24-pin Main Power and 8-pin +12V Power).
• 6. M.2 Slots (Key M): Two M.2 slots supporting M.2 SSD modules. M.2_1 supports PCIe 4.0 x4 & SATA modes, while M.2_2 supports PCIe 3.0 x4 & SATA modes.
• 7. SATA 6Gb/s Ports: Four ports for connecting SATA devices like hard drives and optical drives.
• 8. USB 3.2 Gen 1 Header: For connecting a front panel USB 3.2 Gen 1 module, providing up to 5 Gb/s data transfer.
• 9. USB 2.0 Headers: For connecting front panel USB 2.0 modules, providing up to 480 Mb/s data transfer. Note: Do not connect 1394 cables to USB connectors.
• 10. AURA Addressable Gen 2 Header: For individually addressable RGB WS2812B LED strips (5V). Supports up to 500 LEDs combined.
• 11. AURA RGB Headers: For connecting standard RGB LED strips (12V/G/R/B), supporting up to 3m length.
• 12. Clear CMOS Header: Allows clearing of system setup information (date, time, passwords) by shorting pins.
• 13. COM Port Header: For connecting a serial (COM) port module.
• 14. Front Panel Audio Header: For connecting a chassis-mounted HD audio module.
• 15. S/PDIF Out Header: For an additional Sony/Philips Digital Interface (S/PDIF) port.
• 16. Speaker Header: For the chassis-mounted system warning speaker.
• 17. System Panel Header: Connects to chassis functions like power LED, HDD activity LED, power button, and reset button.
• 18. SPI TPM Header: Supports a Trusted Platform Module (TPM) system for secure storage of keys and data.

1.2.1 Layout Contents

Detailed descriptions of the motherboard components are provided above in the "Motherboard Overview" section.

1.2.2 Rear Panel Connectors

The rear panel provides various ports for connecting external devices:

1. PS/2 Keyboard/Mouse Combo Port: For connecting a PS/2 keyboard or mouse.
2. Video Graphics Adapter (VGA) Port: A 15-pin port for VGA monitors.
3. Ethernet Port: Gigabit connection to a Local Area Network (LAN). Ethernet Port LED Indications:

   Activity/Link LED Status	Description	Speed LED Status	Description
   Off	No link	Off	10Mbps connection
   Orange (Blinking)	Data activity	Orange	100Mbps connection
   Orange (Steady)	Linked	Green	1Gbps connection
   Orange (Blinking then steady)	Ready to wake up from S5 mode

4. Line In Port (light blue): Connects audio sources like tape, CD, or DVD players. In multi-channel configurations, it functions as Rear Speaker Out.
5. Line Out Port (lime): Connects headphones or speakers. In 4, 5.1, and 7.1-channel configurations, it functions as Front Speaker Out.
6. USB 3.2 Gen 1 (up to 5Gbps) Ports: Connects to USB 3.2 Gen 1 devices.
7. DVI-D Port: For DVI-D compatible devices. Note: DVI-D cannot output RGB signals to CRT and is not compatible with DVI-I.
8. HDMITM Port: High-Definition Multimedia Interface port, HDCP compliant for HD DVD, Blu-ray, and protected content playback.
9. USB 3.2 Gen 2 (up to 10Gbps) Ports (teal blue, Type A): Connects to USB 3.2 Gen 2 devices.
10. Microphone Port (pink): Connects a microphone.

Audio Port Configuration:

To configure 7.1-channel audio, use a chassis with an HD audio module in the front panel.

1.3 Central Processing Unit (CPU)

The motherboard features an AMD Socket AM4 for 3rd Gen AMD Ryzen™ Processors. Ensure you use a CPU designed for the AM4 socket. The CPU fits in only one orientation; do not force it to prevent damage.

CPU Installation:

Apply Thermal Interface Material (TIM) to the CPU heatsink and CPU before installing the heatsink and fan, if necessary.

The process involves opening the socket lever, aligning the CPU with the socket markings, gently placing the CPU, and closing the lever. Then, apply thermal paste and install the cooler.

1.4 System Memory

The motherboard has four DDR4 Dual Inline Memory Module (DIMM) sockets. For dual-channel configuration, install DIMMs in pairs (e.g., DIMM_A1 & DIMM_A2, DIMM_B1 & DIMM_B2).

• Memory sizes can vary between channels; the system uses the lower size for dual-channel and maps excess to single-channel.
• Install DIMMs with the same CAS latency. For optimal compatibility, use modules of the same version or date code from the same vendor.
• DDR4 modules have a different notch than DDR, DDR2, or DDR3; do not install incompatible modules.
• Default memory frequency depends on SPD. Overclocking modules might run at lower frequencies by default.
• For stability with 4 DIMMs, use an efficient memory cooling system.
• Refer to www.asus.com for the latest Memory QVL (Qualified Vendors Lists).

Recommended Memory Configuration:

For dual-channel operation, install DIMMs in pairs: DIMM_A1 and DIMM_A2, or DIMM_B1 and DIMM_B2. For optimal performance, populate both channels with matched DIMMs.

Installing a DIMM:

To install a DIMM, open the clips on the DIMM slot. Align the notch on the DIMM with the notch in the slot. Press down firmly on both ends of the DIMM until the clips snap into place. To remove a DIMM, push down the clips on both ends of the slot and gently pull the DIMM out.

Chapter 2: BIOS and RAID Support

2.1 Knowing BIOS

The ASUS UEFI BIOS provides a user-friendly interface with mouse support, going beyond traditional keyboard-only controls. BIOS stores essential system hardware settings for startup.

Default BIOS settings are usually optimal. Change settings only if prompted by an error message or if installing new hardware requiring specific configurations.

Important Notes:

• When downloading or updating the BIOS file, rename it to PB550MA.CAP for this motherboard.
• BIOS settings and options may vary with BIOS release versions. Refer to the latest version for current options.
• For more information, visit https://www.asus.com/support.

2.2 BIOS Setup Program

Use the BIOS Setup to update BIOS or configure parameters. Navigation keys and onscreen help are provided.

Entering BIOS at Startup: Press <Delete> or <F2> during POST (Power-On Self Test).

Entering BIOS Setup After POST:

• Press <Ctrl>+<Alt>+<Delete> simultaneously.
• Press the reset button on the system chassis.
• Turn the system off and back on, then press <Delete>.

Tips:

• A USB mouse can be used for navigation if connected.
• If the system becomes unstable after changing settings, load default settings using "Load Optimized Defaults" (hotkey <F5>) under the Exit menu.
• If the system fails to boot, clear the CMOS to reset motherboard defaults.
• The BIOS setup program does not support Bluetooth devices.

BIOS can be used in EZ Mode or Advanced Mode. Switch modes using "Setup Mode" in the Boot menu or by pressing the <F7> hotkey.

2.3 ASUS EZ Flash 3

ASUS EZ Flash 3 allows BIOS updates without an OS-based utility. Ensure BIOS default settings are loaded first.

To update BIOS by USB:

• The USB flash disk must be FAT32/16 format with a single partition.
• DO NOT shut down or reset the system during BIOS updates to prevent boot failure.
• Insert the USB flash disk with the latest BIOS file into a USB port.
• Enter Advanced Mode BIOS, navigate to the Tool menu, and select ASUS EZ Flash 3 Utility.
• Select "via Storage Device(s)".
• Press <Tab> to the Drive field, use arrow keys to find the USB flash disk, and press <Enter>.
• Press <Tab> to the Folder field, use arrow keys to find the BIOS file, and press <Enter> to start the update. Reboot upon completion.

2.4 ASUS CrashFree BIOS 3

ASUS CrashFree BIOS 3 is an auto-recovery tool for restoring a corrupted BIOS file. It can restore the BIOS using a USB flash drive containing the BIOS file.

Download the latest BIOS file from https://www.asus.com/support and save it to a USB flash drive.

Recovering the BIOS:

1. Turn on the system.
2. Insert the USB flash drive with the BIOS file into a USB port.
3. The utility automatically checks for the BIOS file and, if found, enters ASUS EZ Flash 3.
4. The system will prompt you to enter BIOS Setup to recover settings. Press <F5> to load default BIOS values for compatibility and stability.

DO NOT shut down or reset the system during the BIOS update process.

2.5 RAID Configurations

The motherboard supports RAID 0, RAID 1, and RAID 10 configurations. For detailed information, refer to the RAID Configuration Guide available at https://www.asus.com/support.

RAID Definitions:

• RAID 0 (Data Striping): Optimizes two identical hard drives for parallel read/write operations, doubling data transfer rates. Requires two new identical hard drives.
• RAID 1 (Data Mirroring): Copies data from one drive to a second drive, providing data protection. If one drive fails, the system uses the mirrored copy. Requires two new drives or one existing and one new drive (new drive must be same size or larger).
• RAID 10: Combines data striping (RAID 0) and data mirroring (RAID 1) for performance and redundancy. Requires four new hard drives or an existing drive plus three new drives.

Appendix

Notices

FCC Compliance Information:

Responsible Party: Asus Computer International. Address: 48720 Kato Rd., Fremont, CA 94538, USA. Phone/Fax: (510)739-3777 / (510)608-4555.

This device complies with Part 15 of the FCC Rules. Operation is subject to two conditions: (1) it may not cause harmful interference, and (2) it must accept any interference received, including interference that may cause undesired operation. This equipment has been tested and found to comply with Class B digital device limits, providing reasonable protection against harmful interference in residential installations. If interference occurs, users are encouraged to try correcting it by reorienting the antenna, increasing separation, connecting to a different circuit, or consulting a dealer/technician.

Compliance Statement of Innovation, Science and Economic Development Canada (ISED):

This device complies with ISED Canada licence-exempt RSS standard(s). Operation is subject to two conditions: (1) this device may not cause interference, and (2) this device must accept any interference, including interference that may cause undesired operation. CAN ICES-3(B)/NMB-3(B).

[French version of ISED compliance statement is also present in the original document.]

VCCI: Japan Compliance Statement Class B ITE

KC: Korea Warning Statement

Google™ License Terms:

Licensed under the Apache License, Version 2.0. Details available at http://www.apache.org/licenses/LICENSE-2.0. Software is distributed "AS IS" without warranties.

Product Environmental Regulation Compliance:

• EU REACH: Information published at http://csr.asus.com/english/REACH.htm.
• EU RoHS: Complies with the EU RoHS Directive. See http://csr.asus.com/english/article.aspx?id=35.
• India RoHS: Complies with India E-Waste (Management) Rules, 2016. Prohibits certain hazardous substances above specified concentrations.
• Vietnam RoHS: Products sold in Vietnam on or after September 23, 2011 meet Vietnam Circular 30/2011/TT-BCT requirements.
• Turkey RoHS: AEEE Yönetmeliine Uygundur.

ASUS Recycling/Takeback Services:

Commitment to environmental protection through recycling and takeback programs. Details at http://csr.asus.com/english/Takeback.htm.

Disposal Instructions: DO NOT throw the motherboard in municipal waste. This symbol [&cross-circle] indicates it should not be placed in municipal waste. Check local regulations for disposal.

DO NOT throw mercury-containing button cell batteries in municipal waste. This symbol [&cross-circle] indicates batteries should not be placed in municipal waste.

Regional Notice for California:

WARNING: Cancer and Reproductive Harm. Visit www.P65Warnings.ca.gov.

Multi-language Declarations of Conformity:

Includes declarations in English, French, German, Italian, Russian, Polish, Portuguese, Spanish, Croatian, Czech, Danish, Dutch, Estonian, Finnish, Hungarian, Latvian, Lithuanian, Norwegian, Slovak, Slovenian, Swedish, Chinese, Turkish, Bulgarian, Greek, Korean, Thai, Vietnamese, and Ukrainian, all stating compliance with relevant EU directives and available at www.asus.com/support.

ASUS Contact Information

ASUSTeK COMPUTER INC.

• Address: 1F., No. 15, Lide Rd., Beitou Dist., Taipei City 112, Taiwan
• Telephone: +886-2-2894-3447
• Fax: +886-2-2890-7798
• Website: https://www.asus.com
• Technical Support: +86-21-38429911, https://qr.asus.com/techserv

ASUS COMPUTER INTERNATIONAL (America)

• Address: 48720 Kato Rd., Fremont, CA 94538, USA
• Telephone: +1-510-739-3777
• Fax: +1-510-608-4555
• Website: https://www.asus.com/us/
• Technical Support: Support fax: +1-812-284-0883, Telephone: +1-812-282-2787, Online support: https://qr.asus.com/techserv

ASUS COMPUTER GmbH (Germany and Austria)

• Address: Harkortstrasse 21-23, 40880 Ratingen, Germany
• Website: https://www.asus.com/de
• Online contact: https://www.asus.com/support/Product/ContactUs/Services/questionform/?lang=de-de
• Technical Support: Telephone (DE): +49-2102-5789557, Telephone (AT): +43-1360-2775461, Online support: https://www.asus.com/de/support