Asus PRIME B550M-K User manual

Motherboard
PRIME B550M-K ARGB

ii
E22193
First Edition
July 2023
Copyright © 2023 ASUSTeK COMPUTER INC. All Rights Reserved.
No part of this manual, including the products and software described in it, may be reproduced,
transmitted, transcribed, stored in a retrieval system, or translated into any language in any form or by any
means, except documentation kept by the purchaser for backup purposes, without the express written
permission of ASUSTeK COMPUTER INC. (“ASUS”).
Product warranty or service will not be extended if: (1) the product is repaired, modied or altered, unless
such repair, modication of alteration is authorized in writing by ASUS; or (2) the serial number of the
product is defaced or missing.
ASUS PROVIDES THIS MANUAL “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OR CONDITIONS OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL ASUS, ITS
DIRECTORS, OFFICERS, EMPLOYEES OR AGENTS BE LIABLE FOR ANY INDIRECT, SPECIAL,
INCIDENTAL, OR CONSEQUENTIAL DAMAGES (INCLUDING DAMAGES FOR LOSS OF PROFITS,
LOSS OF BUSINESS, LOSS OF USE OR DATA, INTERRUPTION OF BUSINESS AND THE LIKE),
EVEN IF ASUS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES ARISING FROM ANY
DEFECT OR ERROR IN THIS MANUAL OR PRODUCT.
SPECIFICATIONS AND INFORMATION CONTAINED IN THIS MANUAL ARE FURNISHED FOR
INFORMATIONAL USE ONLY, AND ARE SUBJECT TO CHANGE AT ANY TIME WITHOUT NOTICE,
AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY ASUS. ASUS ASSUMES NO
RESPONSIBILITY OR LIABILITY FOR ANY ERRORS OR INACCURACIES THAT MAY APPEAR IN THIS
MANUAL, INCLUDING THE PRODUCTS AND SOFTWARE DESCRIBED IN IT.
Products and corporate names appearing in this manual may or may not be registered trademarks or
copyrights of their respective companies, and are used only for identication or explanation and to the
owners’ benet, without intent to infringe.

iii
Contents
Safety information...................................................................................................... iv
About this guide.......................................................................................................... v
Package contents....................................................................................................... vi
PRIME B550M-K ARGB specications summary.................................................... vi
Chapter 1: Product Introduction
1.1 Before you proceed...................................................................................... 1-1
1.2 Motherboard overview ................................................................................. 1-2
1.3 Central Processing Unit (CPU).................................................................... 1-8
1.4 System memory............................................................................................ 1-9
Chapter 2: BIOS and RAID Support
2.1 Knowing BIOS............................................................................................... 2-1
2.2 BIOS Setup program .................................................................................... 2-2
2.3 ASUS EZ Flash 3........................................................................................... 2-3
2.4 ASUS CrashFree BIOS 3.............................................................................. 2-4
2.5 RAID congurations..................................................................................... 2-5
Appendix
Notices ..................................................................................................................... A-1
Warranty................................................................................................................... A-5
ASUS contact information...................................................................................... A-7
Service and Support ............................................................................................... A-7

iv
Safety information
Electrical safety
• To prevent electrical shock hazard, disconnect the power cable from the electrical outlet
before relocating the system.
• When adding or removing devices to or from the system, ensure that the power cables
for the devices are unplugged before the signal cables are connected. If possible,
disconnect all power cables from the existing system before you add a device.
• Before connecting or removing signal cables from the motherboard, ensure that all power
cables are unplugged.
• Seek professional assistance before using an adapter or extension cord. These devices
could interrupt the grounding circuit.
• Ensure that your power supply is set to the correct voltage in your area. If you are not
sure about the voltage of the electrical outlet you are using, contact your local power
company.
• If the power supply is broken, do not try to x it by yourself. Contact a qualied service
technician or your retailer.
Operation safety
• Before installing the motherboard and adding components, carefully read all the manuals
that came with the package.
• Before using the product, ensure all cables are correctly connected and the power cables
are not damaged. If you detect any damage, contact your dealer immediately.
• 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 any area
where it may become wet.
• Place the product on a stable surface.
• If you encounter technical problems with the product, contact a qualied service
technician or your retailer.
• Your motherboard should only be used in environments with ambient temperatures
between 10°C and 35°C.
Button/Coin Batteries Safety Information
WARNING
KEEP OUT OF REACH OF CHILDREN
Swallowing can lead to chemical burns,
perforation of soft tissue, and death.
Severe burns can occur within 2 hours
of ingestion. Seek medical attention
immediately.

v
About this guide
This user guide contains the information you need when installing and conguring the
motherboard.
How this guide is organized
This guide contains the following parts:
• Chapter 1: Product Introduction
This chapter describes the features of the motherboard and the new technology it
supports. It includes descriptions of the switches, jumpers, and connectors on the
motherboard.
• Chapter 2: BIOS and RAID Support
This chapter tells how to boot into the BIOS, upgrade BIOS using the EZ Flash Utility
and support on RAID.
Where to nd more information
Refer to the following sources for additional information and for product and software
updates.
1. ASUS website
The ASUS website (www.asus.com) provides updated information on ASUS hardware
and software products.
2. Optional documentation
Your product package may include optional documentation, such as warranty flyers,
that may have been added by your dealer. These documents are not part of the
standard package.
Conventions used in this guide
To ensure that you perform certain tasks properly, take note of the following symbols used
throughout this user guide.
CAUTION: Information to prevent damage to the components and injuries to
yourself when trying to complete a task.
IMPORTANT: Instructions that you MUST follow to complete a task.
NOTE: Tips and additional information to help you complete a task.

vi
PRIME B550M-K ARGB specications summary
CPU
AMD Socket AM4 for AMD Ryzen™ 5000 Series/ 5000 G-Series/ 4000 G-Series/
3000 Series Desktop Processors*
* Refer to www.asus.com for CPU support list.
Chipset AMD B550 Chipset
Memory
2 x DIMM slots, Max. 64GB, DDR4 Un-buffered Memory*
Dual Channel Memory Architecture
* ECC Memory (ECC mode) support varies by CPU.
* Supported memory types, data rate (speed), and number of DRAM modules vary
depending on the CPU and memory conguration, 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/.
Graphics
1 x DisplayPort**
1 x HDMI™ port***
* Graphics specications may vary between CPU types. Please refer to AMD CPU
specications.
** Supports max. 4K@60Hz as specied in DisplayPort 1.4.
***Supports 4K@60Hz as specied in HDMI 2.1.
Expansion Slots
AMD Ryzen™ 5000 Series/ 3000 Series Desktop Processors
1 x PCIe 4.0 x16 slot (supports x16 mode)
AMD Ryzen™ 5000 G-Series/ 4000 G-Series Desktop Processors
1 x PCIe 3.0 x16 slot (supports x16 mode)
AMD B550 Chipset
1 x PCIe 3.0 x1 slot
* Please check the PCIe bifurcation table on the support site
(https://www.asus.com/support/FAQ/1037507/).
Note: To ensure compatibility of the device installed, please refer to
https://www.asus.com/support/ for the list of supported peripherals.
Storage
Total supports 2 x M.2 slots and 4 x SATA 6Gb/s ports*
AMD Ryzen™ 5000 Series/ 3000 Series Desktop Processors
M.2_1 slot (Key M), type 2242/2260/2280 (supports PCIe 4.0 x4 & SATA modes)
AMD Ryzen™ 5000 G-Series/ 4000 G-Series Desktop Processors
M.2_1 slot (Key M), type 2242/2260/2280 (supports PCIe 3.0 x4 & SATA modes)
AMD B550 Chipset
M.2_2 slot (Key M), type 2242/2260/2280/22110 (supports PCIe 3.0 x4 & SATA modes)
4 x SATA 6Gb/s ports
* AMD RAIDXpert2 Technology supports both PCIe RAID 0/1/10 and SATA RAID 0/1/10.
Ethernet 1 x Realtek 1Gb Ethernet
(continued on the next page)
Package contents
Check your motherboard package for the following items.
Motherboard 1 x PRIME B550M-K ARGB motherboard
Cables 2 x SATA 6Gb/s cables
Miscellaneous 1 x I/O Shield
1 x Screw package for M.2 SSD
Documentation 1 x User guide
If any of the above items is damaged or missing, contact your retailer.

vii
PRIME B550M-K ARGB specications summary
USB
Rear USB (Total 6 ports)
4 x USB 3.2 Gen 1 (5G) ports (4 x Type-A)
2 x USB 2.0 ports (2 x Type-A)
Front USB (Total 7 ports)
1 x USB 3.2 Gen 1 (5G) connector (supports USB Type-C®)
1 x USB 3.2 Gen 1 (5G) header supports 2 additional USB 3.2 Gen 1 ports
2 x USB 2.0 headers support 4 additional USB 2.0 ports
Audio
Realtek 7.1 Surround Sound High Denition 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
4 x USB 3.2 Gen 1 (5G) ports (4 x Type-A)
2 x USB 2.0 ports (2 x Type-A)
1 x DisplayPort
1 x HDMITM port
1 x Realtek 1Gb Ethernet port
3 x Audio jacks
1 x PS/2 Keyboard/Mouse combo port
Internal I/O
Connectors
Fan and Cooling related
1 x 4-pin CPU Fan header
2 x 4-pin Chassis Fan headers
Power related
1 x 24-pin Main Power connector
1 x 8-pin +12V Power connector
Storage related
2 x M.2 slots (Key M)
4 x SATA 6Gb/s ports
USB
1 x USB 3.2 Gen 1 (5G) connector (supports USB Type-C®)
1 x USB 3.2 Gen 1 (5G) header supports 2 additional USB 3.2 Gen 1 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 (AAFP)
1 x S/PDIF Out header
1 x Speaker header
1 x SPI TPM header (14-1 pin)
1 x 10-1 pin System Panel header
(continued on the next page)

viii
PRIME B550M-K ARGB specications summary
Special
Features
ASUS 5X PROTECTION III
- DIGI+ VRM
- LANGuard
- Overvoltage Protection
- SafeSlot Core
- Stainless-Steel Back I/O
ASUS Q-Design
- Q-DIMM
- Q-LED Core
- Q-Slot
ASUS Thermal Solution
- Aluminum heatsink design
Aura Sync
- Addressable Gen 2 headers
Software
Features
ASUS Exclusive Software
Armoury Crate
- Aura Creator
- Aura Sync
AI Suite 3
- Performance And Power Saving Utility
TurboV EVO
EPU
DIGI+ VRM
Fan Xpert 2+
- EZ update
ASUS CPU-Z
Norton 360 Deluxe (60 Days Free Trial)
WinRAR
UEFI BIOS
ASUS EZ DIY
- ASUS CrashFree BIOS 3
- ASUS EZ Flash 3
- ASUS UEFI BIOS EZ Mode
BIOS 128 Mb Flash ROM, UEFI AMI BIOS
Manageability WOL by PME, PXE
Operating
System Windows®11, Windows® 10 64-bit
Form Factor micro-ATX Form Factor
9.6 inch x 8.7 inch (24.4 cm x 22.1 cm)

ix
• Specications are subject to change without notice. Please refer to the ASUS website
for the latest specications.
• For more information on downloading and installing drivers and utilities for your
motherboard, please scan the code below:

x

PRIME B550M-K ARGB 1-1
1
Product Introduction
1.1 Before you proceed
Take note of the following precautions before you install motherboard components or change
any motherboard settings.
• Unplug the power cord from the wall socket before touching any component.
• Before handling components, use a grounded wrist strap or touch a safely grounded
object or a metal object, such as the power supply case, to avoid damaging them due
to static electricity.
• Hold components by the edges to avoid touching the ICs on them.
• Whenever you uninstall any component, place it on a grounded antistatic pad or in the
bag that came with the component.
• Before you install or remove any component, ensure that the ATX power supply is
switched off or the power cord is detached from the power supply. Failure to do so
may cause severe damage to the motherboard, peripherals, or components.
• The pin denitions in this chapter are for reference only. The pin names depend on the
location of the header/jumper/connector.
• For more information on installing your motherboard, please scan the code below:
Chapter 1: Product Introduction

1-2 Chapter 1: Product introduction
1.2 Motherboard overview
SATA
DDR4 DIMM_A (64bit, 288-pin module) DDR4 DIMM_B (64bit, 288-pin module)
DIGI+
VRM
CHA_FAN2
CPU_FAN
COM_DEBUG
CHA_FAN1
TPM
SPEAKER
F_PANEL
AAFP
SPDIF_OUT
CLRTC
SATA6G_4 SATA6G_3
SATA6G_1SATA6G_2
128Mb
BIOS
ATX_12V
ATX_PWR
ADD_GEN 2_1
ADD_GEN 2_3
ADD_GEN 2_2
U32G1_12
U32_C7
BATTERY
U32G1_56
KBMS_USB_56
HDMI
DP
AUDIO
Super
I/O
PCIEX1
2260 2242
2280 2260 2242
PCIEX16
USB_34USB_12
COM
22.1cm(8.7in)
24.4cm(9.6in)
SOCKET AM4
228022110
AMD
B550
Ethernet
Audio
Codec
LAN_U32G1_34
M.2_1(SOCKET3)
4.0 X4
PCIE SATA
V
M.2_2(SOCKET3)
3.0 X4
PCIE
V
9
8
6
7
5
11
413 11121415
3
5 117 24 4
7181610
Unplug the power cord before installing or removing the motherboard. Failure to do so can
cause you physical injury and damage motherboard components.
1.2.1 Layout contents
1. CPU socket
The motherboard comes with an AMD Socket AM4 designed for AMD Ryzen™ 5000 Series/
5000 G-Series/ 4000 G-Series/ 3000 Series Desktop Processors.
For more details, refer to Central Processing Unit (CPU).
2. DDR4 DIMM slots
The motherboard comes with Dual Inline Memory Modules (DIMM) slots designed for DDR4
(Double Data Rate 4) memory modules.
For more details, refer to System memory.

PRIME B550M-K ARGB 1-3
3. Expansion slots
This motherboard supports one PCIe x16 graphics card and one PCIe 3.0 x1 network card,
SCSI card or other card that complies with the PCI Express specication.
4. Fan headers
The Fan headers allow you to connect fans to cool the system.
5. Power connectors
These Power connectors allow you to connect your motherboard to a power supply. The power
supply plugs are designed to t in only one orientation. Find the proper orientation and push
down rmly until the power supply plugs are fully inserted.
Ensure to connect the 8-pin power plug.
We recommend that you use a PSU with a higher power output when conguring a system
with more power-consuming devices. The system may become unstable or may not boot up if
the power is inadequate.
6. M.2 slots (Key M)
The M.2 slots allow you to install M.2 devices such as M.2 SSD modules.
• AMD Ryzen™ 5000 Series/ 3000 Series Desktop Processors
M.2_1 slot (Key M), type 2242/2260/2280 (supports PCIe 4.0 x4 & SATA modes)
• AMD Ryzen™ 5000 G-Series/ 4000 G-Series Desktop Processors
M.2_1 slot (Key M), type 2242/2260/2280 (supports PCIe 3.0 x4 & SATA modes)
• AMD B550 Chipset
M.2_2 slot (Key M), type 2242/2260/2280/22110 (supports PCIe 3.0 x4 & SATA modes)
The M.2 SSD module is purchased separately.
7. SATA 6Gb/s ports
The SATA 6Gb/s ports allow you to connect SATA devices such as optical disc drives and hard
disk drives via SATA cables.
8. USB 3.2 Gen 1 Type-C®Front Panel connector
The USB 3.2 Gen 1 Type-C®connector allows you to connect a USB 3.2
Gen 1 Type-C®module for an additional USB 3.2 Gen 1 Type-C®port
on the front panel. The USB 3.2 Gen 1 Type-C®connector provides data
transfer speeds of up to 5 Gb/s.
The USB 3.2 Gen 1 Type-C®module is purchased separately.
FAN PWM
FAN IN
FAN PWR
GND
FAN PWM
FAN IN
FAN PWR
GND
GND FAN PWR FAN IN FAN PWM
NC
NC
CC1
VBUS
RX1-
RX1+
GND
TX1-
TX1+
VBUS
VBUS
TX2+
TX2-
GND
RX2+
RX2-
GND
D-
D+
CC2
U32G1_C1

1-4 Chapter 1: Product introduction
9. USB 3.2 Gen 1 header
The USB 3.2 Gen 1 header allows you to connect a USB 3.2 Gen 1
module for additional USB 3.2 Gen 1 ports. The USB 3.2 Gen 1
header provides data transfer speeds of up to 5 Gb/s.
The USB 3.2 Gen 1 module is purchased separately.
10. USB 2.0 headers
The USB 2.0 headers allow you to connect USB modules for additional USB
2.0 ports. The USB 2.0 headers provide data transfer speeds of up to 480
Mb/s.
DO NOT connect a 1394 cable to the USB connectors. Doing so will
damage the motherboard!
The USB 2.0 module is purchased separately.
11. Addressable Gen 2 headers
The Addressable Gen 2 headers allow you to connect individually addressable
RGB WS2812B LED strips or WS2812B based LED strips.
The Addressable Gen 2 headers support WS2812B addressable RGB LED strips (5V/Data/
Ground), with a maximum power rating of 3A (5V), and the addressable headers on this
board can handle a combined maximum of 500 LEDs.
Before you install or remove any component, ensure that the power supply is switched off
or the power cord is detached from the power supply. Failure to do so may cause severe
damage to the motherboard, peripherals, or components.
• Actual lighting and color will vary with LED strip.
• If your LED strip does not light up, check if the addressable RGB LED strip is
connected in the correct orientation, and the 5V connector is aligned with the 5V
header on the motherboard.
• The addressable RGB LED strip will only light up when the system is powered on.
• The addressable RGB LED strip is purchased separately.
12. Clear CMOS header
The Clear CMOS header allows you to clear the Real Time Clock (RTC) RAM
in the CMOS, which contains the date, time, system passwords, and system
setup parameters.
To erase the RTC RAM:
1. Turn OFF the computer and unplug the power cord.
2. Short-circuit pin 1-2 with a metal object or jumper cap for about 5-10 seconds.
3. Plug the power cord and turn ON the computer.
4. Hold down the <Del> key during the boot process and enter BIOS setup to
re-enter data.
USB3+5V
IntA_P1_SSRX-
IntA_P1_SSRX+
GND
IntA_P1_SSTX-
IntA_P1_SSTX+
GND
IntA_P1_D-
IntA_P1_D+
GND
PIN 1
USB3+5V
IntA_P2_SSRX-
IntA_P2_SSRX+
GND
IntA_P2_SSTX-
IntA_P2_SSTX+
GND
IntA_P2_D-
IntA_P2_D+
USB 3.2 Gen 1
USB+5V USB_P1- USB_P1+ GND NC
USB+5V
USB_P2-
USB_P2+
GND
PIN 1
USB_12
ADD_GEN 2
+5V
Data
Ground
PIN 1
CLRTC
+3V_BAT GND
PIN 1

PRIME B550M-K ARGB 1-5
DO NOT short-circuit the pins except when clearing the RTC RAM. Short-circuiting or
placing a jumper cap will cause system boot failure!
If the steps above do not help, remove the onboard button cell battery and short the two
pins again to clear the CMOS RTC RAM data. After clearing the CMOS, reinstall the button
cell battery.
13. COM Port header
The COM (Serial) Port header allows you to connect a COM port module.
Connect the COM port module cable to this header, then install the module to
a slot opening on the system chassis.
The COM port module is purchased separately.
14. Front Panel Audio header
The Front Panel Audio header is for a chassis-mounted front panel audio I/O
module that supports HD Audio. Connect one end of the front panel audio I/O
module cable to this header.
We recommend that you connect a high-denition front panel audio
module to this header to avail of the motherboard’s high-denition audio
capability.
15. S/PDIF Out header
The S/PDIF Out header allows you to connect the Sony/Philips Digital
Interface (S/PDIF) Out module.
The S/PDIF module is purchased separately.
16. Speaker header
The 4-pin header is for the chassis-mounted system warning speaker. The
speaker allows you to hear system beeps and warnings.
17. SPI TPM header
This header supports a Trusted Platform Module (TPM)
system with a Serial Peripheral Interface (SPI), allowing you to
securely store keys, digital certicates, passwords, and data.
A TPM system also helps enhance network security, protects
digital identities, and ensures platform integrity.
The TPM module is purchased separately.
PIN 1
RXD
DTR
DSR
CTS
COM
DCD
TXD
GND
RTS
RI
AAFP
AGND NC SENSE1_RETUR SENSE2_RETUR
PORT1 L
PORT1 R PORT2 R
SENSE_SEND
PORT2 L
HD-audio-compliant
pin definition
SPDIF_OUT
+5V SPDIFOUT GND
+5V GND GND Speaker Out
SPEAKER
PIN 1
TPM
PIN 1
SPI_TPM_PWR
SPI_TPM_RST#
NC
SPI_PWR
SPI_CS0#_R
SPI_MISO
SPI_HOLD#_R
SPI_TPM_IRQ#
SPI_TPM_CS#
SPI_BIOS_WP#
GND
SPI_CLK
SPI_MOSI

1-6 Chapter 1: Product introduction
18. System Panel header
This header supports several chassis-mounted functions.
• System Power LED header (+PWR_LED-)
The 2-pin header allows you to connect the System Power LED. The
System Power LED lights up when the system is connected to a power
source, or when you turn on the system power, and blinks when the
system is in sleep mode.
• Storage Device Activity LED header (+HDD_LED-)
The 2-pin header allows you to connect the Storage Device Activity LED.
The Storage Device Activity LED lights up or blinks when data is read from or written to
the storage device or storage device add-on card.
• Power Button/Soft-off Button header (PWR_BTN)
The 2-pin header allows you to connect the system power button. Press the power
button to power up the system, or put the system into sleep or soft-off mode
(depending on the operating system settings).
• Reset Button header (RESET)
The 2-pin header allows you to connect the chassis-mounted reset button. Press the
reset button to reboot the system.
PIN 1
PWR_BTN
PWR_LED+ PWR_LED- PWR GND
HDD_LED+
HDD_LED-
Ground
HWRST#
(NC)
F_PANEL
+PWR_LED-
+HDD_LED- RESET
1.2.2 Rear panel connectors
1
9
2 3 4
56 7 8
1. PS/2 Keyboard/Mouse combo port. This port is for a PS/2 keyboard or mouse.
2. Ethernet port. This port allows Gigabit connection to a Local Area Network (LAN)
through a network hub. Refer to the table below for the Ethernet port LED indications.
Ethernet port LED indications
Speed LED
Status Description
OFF 10 Mbps connection
ORANGE 100 Mbps connection
GREEN 1 Gbps connection
Activity Link LED
Status Description
OFF No link
ORANGE Linked
BLINKING Data activity
ACT/LINK
LED
SPEED
LED
Ethernet port

PRIME B550M-K ARGB 1-7
3. Line In port (light blue). This port connects the tape, CD, DVD player, or other audio
sources.
4. Line Out port (lime). This port connects a headphone or a speaker. In 4-channel,
5.1-channel, and 7.1-channel congurations, the function of this port becomes Front
Speaker Out.
5. USB 2.0 ports. These Universal Serial Bus (USB) ports are for USB 2.0 devices.
6. DisplayPort. This port is for a DisplayPort-compatible device.
7. HDMITM port. This port is for a High-Denition Multimedia Interface (HDMITM)
connector, and is HDCP compliant allowing playback of HD DVD, Blu-ray, and other
protected content.
8. USB 3.2 Gen 1 (up to 5Gbps) ports. These Universal Serial Bus (USB) ports connect
to USB 3.2 Gen 1 devices.
9. Microphone port (pink). This port connects a microphone.
Refer to the audio conguration table below for the function of the audio ports in 2, 4, 5.1,
or 7.1-channel conguration.
Audio 2, 4, 5.1 or 7.1-channel conguration
Port 2-channel 4-channel 5.1-channel 7.1-channel
Light Blue
(Rear panel) - Rear Speaker Out Rear Speaker Out Rear Speaker Out
Lime
(Rear panel) Front Speaker Out Front Speaker Out Front Speaker Out Front Speaker Out
Pink
(Rear panel) - - Center/Subwoofer Center/Subwoofer
Lime
(Front panel) - - - Side Speaker Out
Pink
(Front panel) - - - -
To congure a 7.1-channel audio output:
Use a chassis with HD audio module in the front panel to support a 7.1-channel audio
output.

1-8 Chapter 1: Product introduction
1.3 Central Processing Unit (CPU)
The motherboard comes with an AMD Socket AM4 designed for
AMD Ryzen™ 5000 Series/ 5000 G-Series/ 4000 G-Series/ 3000
Series Desktop Processors.
Unplug all power cables before installing the CPU.
The AM4 socket has a different pinout design. Ensure that you use a CPU designed for the
AM4 socket. The CPU ts in only one correct orientation. DO NOT force the CPU into the
socket to prevent bending the connectors on the socket and damaging the CPU!
Installing the CPU
Apply the Thermal Interface Material to the CPU heatsink and CPU before you install the
heatsink and fan if necessary.
1
3
2
4

PRIME B550M-K ARGB 1-9
1.4 System memory
This motherboard comes with two Double Data Rate 4 (DDR4) Dual Inline Memory Module
(DIMM) sockets. The figure illustrates the location of the DDR4 DIMM sockets:
Channel Sockets
Channel A DIMM_A
Channel B DIMM_B
DIMM_A
DIMM_B
A DDR4 memory module is notched differently from a DDR, DDR2, or DDR3 module. DO
NOT install a DDR, DDR2, or DDR3 memory module to the DDR4 slot.
• You may install varying memory sizes in Channel A and Channel B. The system
maps the total size of the lower-sized channel for the dual-channel conguration. Any
excess memory from the higher-sized channel is then mapped for single-channel
operation.
• You may install 2 GB, 4 GB, 8 GB, 16 GB, and 32 GB unbuffered DDR4 DIMMs into
the DIMM sockets.
• The default memory operation frequency is dependent on its Serial Presence Detect
(SPD), which is the standard way of accessing information from a memory module.
Under the default state, some memory modules for overclocking may operate at a
lower frequency than the vendor-marked value.
• For system stability, use a more efcient memory cooling system to support a full
memory load.
• Always install DIMMs with the same CAS latency. For optimal compatibility, we
recommend that you install memory modules of the same version or date code (D/C)
from the same vendor. Check with the retailer to get the correct memory modules.
• Supported memory types, data rate (speed), and number of DRAM modules vary
depending on the CPU and memory conguration, 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/.
Recommended memory congurations
DIMM_B
DIMM_ADIMM_A
DIMM_B

1-10 Chapter 1: Product introduction
To remove a DIMM
BA
Installing a DIMM
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3