Table of Contents
ASUS PRIME B550M-K User Manual
Displayed below is the user manual for PRIME B550M-K by ASUS which is a product in the Motherboards category. This manual has pages.
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Motherboard
PRIME B550M-K
ii
E16604
First Edition
April 2020
Copyright © 2020 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, modied or altered, unless
such repair, modication 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
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Products and corporate names appearing in this manual may or may not be registered trademarks or
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Offer to Provide Source Code of Certain Software
This product contains copyrighted software that is licensed under the General Public License (“GPL”),
under the Lesser General Public License Version (“LGPL”) and/or other Free Open Source Software
Licenses. Such software in this product is distributed without any warranty to the extent permitted by the
applicable law. Copies of these licenses are included in this product.
Where the applicable license entitles you to the source code of such software and/or other additional data,
you may obtain it for a period of three years after our last shipment of the product, either
(1) for free by downloading it from https://www.asus.com/support/
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In your request please provide the name, model number and version, as stated in the About Box of the
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archives, etc. to this email address).
iii
Contents
Safety information ...................................................................................................... iv
About this guide .......................................................................................................... v
Package contents ....................................................................................................... vi
PRIME B550M-K specifications summary................................................................ vi
Chapter 1 Product introduction
1.1 Before you proceed ......................................................................................1-1
1.2 Motherboard overview .................................................................................1-1
1.3 Central Processing Unit (CPU) ....................................................................1-7
1.4 System memory ............................................................................................1-8
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 configurations .....................................................................................2-5
Appendix
Notices ..................................................................................................................... A-1
ASUS contact information ...................................................................................... A-6
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 qualied 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 be exposed to moisture.
• Place the product on a stable surface.
• If you encounter technical problems with the product, contact a qualied service
technician or your retailer.
• Your motherboard should only be used in environments with ambient temperatures
between 0°C and 40°C.
v
About this guide
This user guide contains the information you need when installing and conguring 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 find more information
Refer to the following sources for additional information and for product and software
updates.
1. ASUS website
The ASUS website provides updated information on ASUS hardware and software
products. Refer to the ASUS contact information.
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 manual.
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 specifications summary
CPU AMD Socket AM4 for 3rd Gen AMD Ryzen™ Processors*
*Refer to www.asus.com for CPU support list.
Chipset AMD B550 Chipset
Memory
3rd Gen AMD Ryzen™ Processors
4 x DIMM, Max. 128GB, DDR4 4400(O.C.)/4000(O.C.)/3866(O.C.)/3600
(O.C.)/3466(O.C.)/3200/3000/2800/2666/2400/2133 MHz, Un-buffered
Memory*
Dual Channel Memory Architecture
*ECC Memory (ECC mode) support varies by CPU.
*Refer to www.asus.com for the Memory QVL (Qualified Vendors Lists).
Graphics
1 x D-Sub
1 x DVI-D
1 x HDMITM 2.1(4K@60HZ)
Expansion Slots
3rd Gen AMD Ryzen™ Processors
1 x PCIe 4.0 x16 slot (supports x16 mode)
AMD B550 Chipset
2 x PCIe 3.0 x1 slots
Storage
Total supports 2 x M.2 slots and 4 x SATA 6Gb/s ports
3rd Gen AMD Ryzen™ Processors
M.2_1 slot (Key M), type 2242/2260/2280/22110 (supports PCIe 4.0 x4 &
SATA modes)
AMD B550 Chipset
M.2_2 slot (Key M), type 2242/2260/2280 (supports PCIe 3.0 x4 & SATA
modes)
4 x SATA 6Gb/s ports
Support Raid 0, 1, 10
Ethernet 1 x Realtek RTL8111H 1Gb Ethernet
(continued on the next page)
Package contents
Check your motherboard package for the following items.
Motherboard 1 x PRIME B550M-K motherboard
Cables 2 x SATA 6Gb/s cables
Miscellaneous 1 x I/O Shield
1 x M.2 SSD screw package
Application DVD 1 x Support DVD
Documentation 1 x User manual
If any of the above items is damaged or missing, contact your retailer.
vii
PRIME B550M-K specifications summary
USB
Rear USB (Total 6 ports)
2 x USB 3.2 Gen 2 ports (2 x Type-A)
4 x USB 3.2 Gen 1 ports (4 x Type-A)
Front USB (Total 6 ports)
1 x USB 3.2 Gen 1 header supports additional 2 USB 3.2 Gen 1 ports
2 x USB 2.0 headers support additional 4 USB 2.0 ports
Audio
Realtek ALC887 7.1-Channel 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
- LED-illuminated audio trace path design
- Premium Japanese audio capacitors
- Dedicated audio PCB layers
* A chassis with an HD audio module in the front panel is required to support
7.1-channel audio output.
Back Panel I/O Ports
2 x USB 3.2 Gen 2 ports (2 x Type-A)
4 x USB 3.2 Gen 1 ports (4 x Type-A)
1 x D-Sub port
1 x DVI-D port
1 x HDMITM port
1 x Realtek RTL8111H 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 header supports additional 2 USB 3.2 Gen 1 ports
2 x USB 2.0 headers support additional 4 USB 2.0 ports
Miscellaneous
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 (14-1pin)
1 x 10-1 pin System Panel header
(continued on the next page)
viii
PRIME B550M-K specifications summary
Special Features
ASUS 5X PROTECTION III
- ASUS DIGI+ VRM
- ASUS LANGuard
- ASUS Overvoltage Protection
- ASUS SafeSlot Core
- ASUS Stainless-Steel Back I/O
ASUS Q-Design
- ASUS Q-DIMM
- ASUS Q-Slot
ASUS Thermal Solution
- Aluminum heatsink design
ASUS Lighting Control
Software Features
ASUS Exclusive Software
Armoury Crate
AI Suite 3
- Performance And Power Saving Utility
TurboV EVO
EPU
Digi+ VRM
Fan Xpert 2+
- EZ update
ASUS CPU-Z
AI Charger
DAEMON Tools
Norton Anti-virus software (Free Trial for 60 days)
WinRAR
UEFI BIOS
ASUS EZ DIY
- ASUS CrashFree BIOS 3
- ASUS EZ Flash 3
- ASUS UEFI BIOS EZ Mode
BIOS 256 Mb Flash ROM, UEFI AMI BIOS
Manageability WOL by PME, PXE
Operating System Windows® 10 - 64 bit
Form Factor mATX Form Factor
9.6 inch x 9.6 inch ( 24.4 cm x 24.4 cm )
Specications are subject to change without notice. Refer to the ASUS website for the
latest specications.
ASUS PRIME B550M-K 1-1
Product introduction
1
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.
• 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.
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 Motherboard overview
Place this
side towards
the rear of the
chassis
DDR4 DIMM_A1 (64bit, 288-pin module)
DDR4 DIMM_A2* (64bit, 288-pin module)
DDR4 DIMM_B1 (64bit, 288-pin module)
DDR4 DIMM_B2* (64bit, 288-pin module)
DIGI+
VRM
CHA_FAN2
CPU_FAN
COM_DEBUG
CHA_FAN1
TPM
SPEAKER
F_PANEL
AAFP
SPDIF_OUT
SATA6G_4
CLRTC
SATA6G_3 SATA6G_2 SATA6G_1
256Mb
BIOS
EATX12V
EATXPWR
U32G1_12
BATTERY
U32G2_56
LAN_U32G1_34
KBMS
_U32G1
_78
DVI
VGA
HDMI
AUDIO
Super
I/O
PCIEX1_1
PCIEX1_2
M.2_1(SOCKET3)
M.2_2(SOCKET3)
22110
2260 2242
2280 2260 2242
PCIEX16
USB34USB12
COM
24.4cm(9.6in)
24.4cm(9.6in)
SOCKET AM4
RTL
8111H
ALC
887
2280
AMD
B550
8
10
6
5
4111213
3
5 115 24 4
716149
6
1-2 Chapter 1: Product introduction
1.2.1 Layout contents
1. CPU socket
The motherboard comes with an AMD Socket AM4 designed for 3rd Gen AMD Ryzen™
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.
3. Expansion slots
This motherboard supports one PCIe x16 graphics card and two PCIe 3.0 x1 network cards,
SCSI cards and other cards that comply with the PCI Express specication.
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.
• For a fully congured system, we recommend that you use a power supply unit
(PSU) that complies with ATX 12V Specication 2.0 (or later version) and provides a
minimum power of 350W.
• We recommend that you use a PSU with a higher power output when conguring a
system with more power-consuming devices. The system may become unstable or
may not boot up if the power is inadequate.
• If you are uncertain about the minimum power supply requirement for your system, we
recommend you to refer to online resources for Power Supply Wattage Calculator.
6. M.2 Slots (Key M)
The M.2 slots allow you to install M.2 devices such as M.2 SSD modules.
• For 3rd Gen AMD Ryzen™ Processors，M.2_1 slot (Key M), type
2242/2260/2280/22110 (supports PCIe 4.0 x4 & SATA modes).
• For AMD B550 Chipset, M.2_2 slot (Key M), type 2242/2260/2280 (supports PCIe 3.0
x4 & SATA modes).
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 a SATA cable.
GND
FAN PWR
FAN IN
FAN PWM
FAN PWM
FAN IN
FAN PWR
GND
ASUS PRIME B550M-K 1-3
8. 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.
9. 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.
10. Clear CMOS header
This header allows you to clear the CMOS RTC RAM data of the system setup
information such as date, time, and system passwords.
To erase the RTC RAM:
1. Turn OFF the computer and unplug the power cord.
2. Use a metal object such as a screwdriver to short the two pins.
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.
If the steps above do not help, remove the onboard battery and short the two pins again to
clear the CMOS RTC RAM data. After clearing the CMOS, reinstall the battery.
11. COM Port header
This header is for a serial (COM) port. Connect the serial port module cable to
this header, then install the module to a slot opening at the back of the system
chassis.
12. Front panel audio header
This header is for a chassis-mounted front panel audio I/O module that
supports HD audio standard. Connect one end of the front panel audio
I/O module cable to this header.
• We recommend that you connect a high-denition front panel
audio module to this header to avail of the motherboard’s high-
denition audio capability.
• If you want to connect a high-denition front panel audio
module to this header, set the Front Panel Type item in the
BIOS setup to [HD Audio]. By default, this header is set to [HD
Audio].
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+
PIN 1
USB+5V
USB_P1-
USB_P1+
GND
NC
USB+5V
USB_P2-
USB_P12+
GND
CLRTC
+3V_BAT
GND
PIN 1
PIN 1
COM
DCD
TXD
GND
RTS
RI
RXD
DTR
DSR
CTS
AAFP
AGND
NC
SENSE1_RETUR
SENSE2_RETUR
PORT1 L
PORT1 R
PORT2 R
SENSE_SEND
PORT2 L
HD-audio-compliant
pin definition
1-4 Chapter 1: Product introduction
13. S/PDIF Out header
This header is for an additional Sony/Philips Digital Interface (S/PDIF) port.
Connect the S/PDIF Out module cable to this header, then install the module to
a slot opening at the back of the system chassis.
14. Speaker header
The 4-pin header is for the chassis-mounted system warning speaker. The
speaker allows you to hear system beeps and warnings.
15. 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
certicates, passwords, and data. A TPM system also helps enhance
network security, protects digital identities, and ensures platform integrity.
16. 10-1 pin System Panel header
This header supports several chassis-mounted functions.
• System power LED (2-pin +PWR_LED-)
This 2-pin header is for the system power LED. Connect the chassis
power LED cable to this header. The system power LED lights up when
you turn on the system power, and blinks when the system is in sleep
mode.
• Hard disk drive activity LED (2-pin +HDD_LED-)
This 2-pin header is for the HDD Activity LED. Connect the HDD Activity LED cable to
this header. The HDD LED lights up or flashes when data is read from or written to the
HDD.
• Power button/Soft-off button (2-pin PWR_BTN)
This header is for the system power button.
• Reset button (2-pin RESET)
This 2-pin header is for the chassis-mounted reset button for system reboot without
turning off the system power.
TPM
PIN 1
T_SPI_MOSI
T_SPI_CLK
GND
F_BIOS_WP#_R
S_SPI_TPM_CS2#
S_SPI_TPM_IRQ#
F_SPI_HOLD#_R
T_SPI_MISO
F_SPI_CS0#_R
+3V_SPI
F2_SPI_CS1#_R
S_PLTRST#
VCCSPI
PIN 1
PWR_BTN
PWR_LED+
PWR_LED-
PWR
GND
HDD_LED+
HDD_LED-
Ground
HWRST#
(NC)
F_PANEL
+PWR_LED-
+HDD_LED- RESET
SPDIF_OUT
+5V
SPDIFOUT
GND
+5V
GND
GND
Speaker Out
SPEAKER
PIN 1
ASUS PRIME B550M-K 1-5
1.2.2 Rear panel connectors
Ethernet port
Speed
LED
Activity Link
LED
Activity/Link LED Speed LED
Status Description Status Description
Off No link Off 10Mbps connection
Orange Linked Orange 100Mbps connection
Orange (Blinking) Data activity Green 1Gbps connection
Orange (Blinking
then steady)
Ready to wake
up from S5 mode
1 2
6 8 9 6 10
3 4 5
7
Ethernet port LED indications
1. PS/2 Keyboard/Mouse combo port. This port is for a PS/2 keyboard or mouse.
2. Video Graphics Adapter (VGA) port. This 15-pin port is for a VGA monitor or other
VGA-compatible devices.
3. 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.
4. Line In port (light blue). This port connects the tape, CD, DVD player, or other audio
sources.
5. Line Out port (lime). This port connects a headphone or a speaker. In 4-channel,
5.1-channel, and 7.1-channel congurations, the function of this port becomes Front
Speaker Out.
6. USB 3.2 Gen 1 (up to 5Gbps) ports. These 9-pin Universal Serial Bus (USB) ports
connect to USB 3.2 Gen 1 devices.
7. DVI-D port. This port is for any DVI-D compatible device.
DVI-D can not be converted to output from RGB Signal to CRT and is not compatible with
DVI-I.
8. HDMITM port. This port is for a High-Denition Multimedia Interface (HDMITM)
connector, and is HDCP compliant allowing playback of HD DVD, Blu-ray, and other
protected content.
1-6 Chapter 1: Product introduction
10. Microphone port (pink). This port connects a microphone.
Refer to the audio conguration table for the function of the audio ports in 2, 4, 5.1, or
7.1-channel conguration.
Audio 2, 4, 5.1 or 7.1-channel configuration
Port Headset
2-channel 4-channel 5.1-channel 7.1-channel
Light Blue
(Rear panel) Line In Rear Speaker Out Rear Speaker Out Rear Speaker Out
Lime (Rear panel) Line Out Front Speaker Out Front Speaker Out Front Speaker Out
Pink (Rear panel) Mic In Mic In Bass/Center Bass/Center
Lime (Front panel) — — — Side Speaker Out
To configure 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.
9. USB 3.2 Gen 2 (up to 10Gbps) ports (teal blue, Type A). These 9-pin Universal
Serial Bus 3.2 (USB 3.2) ports are for USB 3.2 Gen 2 devices.
ASUS PRIME B550M-K 1-7
1.3 Central Processing Unit (CPU)
The motherboard comes with an AMD Socket AM4 designed for 3rd
Gen AMD Ryzen™ Processors.
Unplug all power cables before installing 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
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!
1-8 Chapter 1: Product introduction
1.4 System memory
This motherboard comes with four Double Data Rate 4 (DDR4) Dual Inline Memory Module
(DIMM) sockets. The gure illustrates the location of the DDR4 DIMM sockets:
• 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 conguration. Any
excess memory from the higher-sized channel is then mapped for single-channel
operation.
• 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.
• 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.
Recommended memory configuration
• 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 efcient memory cooling system to support a full
memory load (4 DIMMs).
• Refer to www.asus.com for the latest Memory QVL (Qualied Vendors Lists).
DIMM_B2*
DIMM_A1
DIMM_A2*
DIMM_B2*
DIMM_A2*
DIMM_B1
DIMM_B2*
Channel Sockets
Channel A DIMM_A1 & DIMM_A2*
Channel B DIMM_B1 & DIMM_B2*
DIMM_B1
DIMM_B2*
DIMM_A1
DIMM_A2*
ASUS PRIME B550M-K 1-9
Installing a DIMM
1 2
B
A
A
To remove a DIMM
B
A
1-10 Chapter 1: Product introduction
ASUS PRIME B550M-K 2-1
BIOS and RAID Support
2
2.1 Knowing BIOS
The new ASUS UEFI BIOS is a Unied Extensible Interface that complies with UEFI
architecture, offering a user-friendly interface that goes beyond the traditional keyboard-
only BIOS controls to enable a more flexible and convenient mouse input. You can easily
navigate the new UEFI BIOS with the same smoothness as your operating system. The
term “BIOS” in this user manual refers to “UEFI BIOS” unless otherwise specied.
BIOS (Basic Input and Output System) stores system hardware settings such as storage
device conguration, overclocking settings, advanced power management, and boot
device conguration that are needed for system startup in the motherboard CMOS. In
normal circumstances, the default BIOS settings apply to most conditions to ensure
optimal performance. DO NOT change the default BIOS settings except in the following
circumstances:
• An error message appears on the screen during the system bootup and requests you
to run the BIOS Setup.
• You have installed a new system component that requires further BIOS settings or
update.
Inappropriate BIOS settings may result to instability or boot failure. We strongly
recommend that you change the BIOS settings only with the help of a trained service
personnel.
• When downloading or updating the BIOS le, rename it as PB550MK.CAP for this
motherboard.
• BIOS settings and options may vary due to different BIOS release versions. Please
refer to the latest BIOS version for settings and options.
For more information on BIOS congurations, please refer to
https://www.asus.com/support, or download the BIOS manual
by scanning the QR code.
2-2 Chapter 2: BIOS and RAID Support
2.2 BIOS setup program
Use the BIOS Setup to update the BIOS or congure its parameters. The BIOS screens
include navigation keys and brief onscreen help to guide you in using the BIOS Setup
program.
Entering BIOS at startup
To enter BIOS Setup at startup, press <Delete> or <F2> during the Power-On Self Test
(POST). If you do not press <Delete> or <F2>, POST continues with its routines.
Entering BIOS Setup after POST
To enter BIOS Setup after POST:
• Press <Ctrl>+<Alt>+<Delete> simultaneously.
• Press the reset button on the system chassis.
• Press the power button to turn the system off then back on. Do this option only if you
failed to enter BIOS Setup using the rst two options.
After doing either of the three options, press <Delete> key to enter BIOS.
• Ensure that a USB mouse is connected to your motherboard if you want to use the
mouse to control the BIOS setup program.
• If the system becomes unstable after changing any BIOS setting, load the default
settings to ensure system compatibility and stability. Select the Load Optimized
Defaults item under the Exit menu or press hotkey <F5>.
• If the system fails to boot after changing any BIOS setting, try to clear the CMOS and
reset the motherboard to the default value.
• The BIOS setup program does not support Bluetooth devices.
BIOS menu screen
The BIOS Setup program can be used under two modes: EZ Mode and Advanced Mode.
You can change modes from Setup Mode in Boot menu or by pressing the <F7> hotkey.
ASUS PRIME B550M-K 2-3
2.3 ASUS EZ Flash 3
The ASUS EZ Flash 3 feature allows you to update the BIOS without using an OS-based
utility.
Ensure to load the BIOS default settings to ensure system compatibility and stability. Select
the Load Optimized Defaults item under the Exit menu or press hotkey <F5>.
To update the BIOS by USB:
• This function can support devices such as a USB flash disk with FAT 32/16 format and
single partition only.
• DO NOT shut down or reset the system while updating the BIOS to prevent system
boot failure!
1. Insert the USB flash disk that contains the latest BIOS le to the USB port.
2. Enter the Advanced Mode of the BIOS setup program. Go to the Tool menu to select
ASUS EZ Flash 3 Utility and press <Enter>.
3. Select via Storage Device(s).
4. Press <Tab> to switch to the Drive eld.
5. Press the Up/Down arrow keys to nd the USB flash disk that contains the latest BIOS,
and then press <Enter>.
6. Press <Tab> to switch to the Folder eld.
7. Press the Up/Down arrow keys to nd the BIOS le, and then press <Enter> to perform
the BIOS update process. Reboot the system when the update process is done.
2-4 Chapter 2: BIOS and RAID Support
2.4 ASUS CrashFree BIOS 3
The ASUS CrashFree BIOS 3 utility is an auto recovery tool that allows you to restore the
BIOS le when it fails or gets corrupted during the updating process. You can restore a
corrupted BIOS le using a USB flash drive that contains the BIOS le.
If you want to use the latest BIOS le, download the le at https://www.asus.com/support,
and save it to a USB flash drive.
Recovering the BIOS
To recover the BIOS:
1. Turn on the system.
2. Insert the USB flash drive containing the BIOS le to the USB port.
3. The utility automatically checks the devices for the BIOS le. When found, the utility
reads the BIOS le and enters ASUS EZ Flash 3 automatically.
4. The system requires you to enter BIOS Setup to recover the BIOS setting. To ensure
system compatibility and stability, we recommend that you press <F5> to load default
BIOS values.
DO NOT shut down or reset the system while updating the BIOS! Doing so can cause
system boot failure!
ASUS PRIME B550M-K 2-5
2.5 RAID configurations
The motherboard supports RAID 0, RAID1, and RAID10 conguration.
RAID definitions
RAID 0 (Data striping) optimizes two identical hard disk drives to read and write data in
parallel, interleaved stacks. Two hard disks perform the same work as a single drive but at a
sustained data transfer rate, double that of a single disk alone, thus improving data access
and storage. Use of two new identical hard disk drives is required for this setup.
RAID 1 (Data mirroring) copies and maintains an identical image of data from one drive to
a second drive. If one drive fails, the disk array management software directs all applications
to the surviving drive as it contains a complete copy of the data in the other drive. This RAID
conguration provides data protection and increases fault tolerance to the entire system. Use
two new drives or use an existing drive and a new drive for this setup. The new drive must be
of the same size or larger than the existing drive.
RAID 10 is data striping and data mirroring combined without parity (redundancy data) having
to be calculated and written. With the RAID 10 conguration you get all the benets of both
RAID 0 and RAID 1 congurations. Use four new hard disk drives or use an existing drive
and three new drives for this setup.
For more information on conguring your RAID sets, please
refer to the RAID Configuration Guide which you can nd at
https://www.asus.com/support, or by scanning the QR code.
2-6 Chapter 2: BIOS and RAID Support
Appendix
Notices
FCC Compliance Information
Responsible Party: Asus Computer International
Address: 48720 Kato Rd., Fremont, CA 94538, USA
Phone / Fax No: (510)739-3777 / (510)608-4555
This device complies with part 15 of the FCC Rules. Operation is subject to the following
two conditions: (1) This device may not cause harmful interference, and (2) this device must
accept any interference received, including interference that may cause undesired operation.
This equipment has been tested and found to comply with the limits for a Class B digital
device, pursuant to part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference in a residential installation. This equipment
generates, uses and can radiate radio frequency energy and, if not installed and used in
accordance with the instructions, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular installation. If
this equipment does cause harmful interference to radio or television reception, which can be
determined by turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to which the receiver is
connected.
- Consult the dealer or an experienced radio/TV technician for help.
ASUS PRIME B550M-K A-1
VCCI: Japan Compliance Statement
Class B ITE
KC: Korea Warning Statement
Compliance Statement of Innovation, Science and Economic
Development Canada (ISED)
This device complies with Innovation, Science and Economic Development Canada licence
exempt RSS standard(s). Operation is subject to the following two conditions: (1) this device
may not cause interference, and (2) this device must accept any interference, including
interference that may cause undesired operation of the device.
CAN ICES-3(B)/NMB-3(B)
Déclaration de conformité de Innovation, Sciences et
Développement économique Canada (ISED)
Le présent appareil est conforme aux CNR d’Innovation, Sciences et Développement
économique Canada applicables aux appareils radio exempts de licence. L’exploitation est
autorisée aux deux conditions suivantes : (1) l’appareil ne doit pas produire de brouillage,
et (2) l’utilisateur de l’appareil doit accepter tout brouillage radioélectrique subi, même si le
brouillage est susceptible d’en compromettre le fonctionnement.
CAN ICES-3(B)/NMB-3(B)
A-2 Appendices
Google™ License Terms
Copyright© 2020 Google Inc. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the “License”); you may not use this le
except in compliance with the License. You may obtain a copy of the License at:
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the
License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
ANY KIND, either express or implied.
See the License for the specic language governing permissions and limitations under the
License.
Declaration of compliance for product environmental
regulation
ASUS follows the green design concept to design and manufacture our products, and
makes sure that each stage of the product life cycle of ASUS product is in line with global
environmental regulations. In addition, ASUS disclose the relevant information based on
regulation requirements.
Please refer to http://csr.asus.com/Compliance.htm for information disclosure based on
regulation requirements ASUS is complied with:
EU REACH and Article 33
Complying with the REACH (Registration, Evaluation, Authorisation, and Restriction of
Chemicals) regulatory framework, we published the chemical substances in our products at
ASUS REACH website at http://csr.asus.com/english/REACH.htm.
EU RoHS
This product complies with the EU RoHS Directive. For more details, see
http://csr.asus.com/english/article.aspx?id=35
India RoHS
This product complies with the “India E-Waste (Management) Rules, 2016” and prohibits
use of lead, mercury, hexavalent chromium, polybrominated biphenyls (PBBs) and
polybrominated diphenyl ethers (PBDEs) in concentrations exceeding 0.1% by weight in
homogenous materials and 0.01% by weight in homogenous materials for cadmium, except
for the exemptions listed in Schedule II of the Rule.
Vietnam RoHS
ASUS products sold in Vietnam, on or after September 23, 2011,meet the requirements of
the Vietnam Circular 30/2011/TT-BCT.
Các sản phẩm ASUS bán tại Việt Nam, vào ngày 23 tháng 9 năm2011 trở về sau, đều phải đáp ứng
các yêu cầu của Thông tư 30/2011/TT-BCT của Việt Nam.
Turkey RoHS
AEEE Yönetmeliğine Uygundur
ASUS PRIME B550M-K A-3
ASUS Recycling/Takeback Services
ASUS recycling and takeback programs come from our commitment to the highest standards
for protecting our environment. We believe in providing solutions for you to be able to
responsibly recycle our products, batteries, other components as well as the packaging
materials. Please go to http://csr.asus.com/english/Takeback.htm for detailed recycling
information in different regions.
DO NOT throw the motherboard in municipal waste. This product has been designed to
enable proper reuse of parts and recycling. This symbol of the crossed out wheeled bin
indicates that the product (electrical and electronic equipment) should not be placed in
municipal waste. Check local regulations for disposal of electronic products.
DO NOT throw the mercury-containing button cell battery in municipal waste. This symbol
of the crossed out wheeled bin indicates that the battery should not be placed in municipal
waste.
Regional notice for California
WARNING
Cancer and Reproductive Harm -
www.P65Warnings.ca.gov
A-4 Appendices
Română ASUSTeK Computer Inc. declară că acest dispozitiv se conformează
cerinţelor esenţiale şi altor prevederi relevante ale directivelor conexe. Textul
complet al declaraţiei de conformitate a Uniunii Europene se găseşte la:
www.asus.com/support
Srpski ASUSTeK Computer Inc. ovim izjavljuje da je ovaj uređaj u saglasnosti
sa osnovnim zahtevima i drugim relevantnim odredbama povezanih Direktiva.
Pun tekst EU deklaracije o usaglašenosti je dostupan da adresi:
www.asus.com/support
Slovensky Spoločnosť ASUSTeK Computer Inc. týmto vyhlasuje, že toto
zariadenie vyhovuje základným požiadavkám a ostatým príslušným
ustanoveniam príslušných smerníc. Celý text vyhlásenia o zhode pre štáty EÚ
je dostupný na adrese: www.asus.com/support
Slovenščina ASUSTeK Computer Inc. izjavlja, da je ta naprava skladna z
bistvenimi zahtevami in drugimi ustreznimi določbami povezanih direktiv.
Celotno besedilo EU-izjave o skladnosti je na voljo na spletnem mestu:
www.asus.com/support
Español Por la presente, ASUSTeK Computer Inc. declara que este dispositivo
cumple los requisitos básicos y otras disposiciones pertinentes de las
directivas relacionadas. El texto completo de la declaración de la UE de
conformidad está disponible en: www.asus.com/support
Svenska ASUSTeK Computer Inc. förklarar härmed att denna
enhet överensstämmer med de grundläggande kraven och andra
relevanta föreskrifter i relaterade direktiv. Fulltext av EU-försäkran om
överensstämmelse nns på: www.asus.com/support
Українська ASUSTeK Computer Inc. заявляє, що цей пристрій відповідає
основним вимогам та іншим відповідним положенням відповідних
Директив. Повний текст декларації відповідності стандартам ЄС доступний
на: www.asus.com/support
Türkçe AsusTek Computer Inc., bu aygıtın temel gereksinimlerle ve ilişkili
Yönergelerin diğer ilgili koşullarıyla uyumlu olduğunu beyan eder. AB
uygunluk bildiriminin tam metni şu adreste bulunabilir:
www.asus.com/support
Bosanski ASUSTeK Computer Inc. ovim izjavljuje da je ovaj uređaj usklađen
sa bitnim zahtjevima i ostalim odgovarajućim odredbama vezanih direktiva.
Cijeli tekst EU izjave o usklađenosti dostupan je na: www.asus.com/support
English ASUSTeK Computer Inc. hereby declares that this device is in
compliance with the essential requirements and other relevant provisions of
related Directives. Full text of EU declaration of conformity is available at:
www.asus.com/support
Français AsusTek Computer Inc. déclare par la présente que cet appareil est
conforme aux critères essentiels et autres clauses pertinentes des directives
concernées. La déclaration de conformité de l’UE peut être téléchargée à
partir du site Internet suivant : www.asus.com/support
Deutsch ASUSTeK Computer Inc. erklärt hiermit, dass dieses Gerät mit
den wesentlichen Anforderungen und anderen relevanten Bestimmungen
der zugehörigen Richtlinien übereinstimmt. Der gesamte Text der EU-
Konformitätserklärung ist verfügbar unter: www.asus.com/support
Italiano ASUSTeK Computer Inc. con la presente dichiara che questo
dispositivo è conforme ai requisiti essenziali e alle altre disposizioni
pertinenti con le direttive correlate. Il testo completo della dichiarazione di
conformità UE è disponibile all’indirizzo: www.asus.com/support
Русский Компания ASUS заявляет, что это устройство соответствует
основным требованиям и другим соответствующим условиям
соответствующих директив. Подробную информацию, пожалуйста,
смотрите на www.asus.com/support
Български С настоящото ASUSTeK Computer Inc. декларира, че това
устройство е в съответствие със съществените изисквания и другите
приложими постановления на свързаните директиви. Пълният текст на
декларацията за съответствие на ЕС е достъпна на адрес:
www.asus.com/support
Hrvatski ASUSTeK Computer Inc. ovim izjavljuje da je ovaj uređaj sukladan
s bitnim zahtjevima i ostalim odgovarajućim odredbama vezanih direktiva.
Cijeli tekst EU izjave o sukladnosti dostupan je na: www.asus.com/support
Čeština Společnost ASUSTeK Computer Inc. tímto prohlašuje, že
toto zařízení splňuje základní požadavky a další příslušná ustanovení
souvisejících směrnic. Plné znění prohlášení o shodě EU je k dispozici na
adrese: www.asus.com/support
Dansk ASUSTeK Computer Inc. erklærer hermed, at denne enhed er i
overensstemmelse med hovedkravene og andre relevante bestemmelser i
de relaterede direktiver. Hele EU-overensstemmelseserklæringen kan ndes
på: www.asus.com/support
Nederlands ASUSTeK Computer Inc. verklaart hierbij dat dit apparaat
voldoet aan de essentiële vereisten en andere relevante bepalingen van
de verwante richtlijnen. De volledige tekst van de EU-verklaring van
conformiteit is beschikbaar op: www.asus.com/support
Eesti Käesolevaga kinnitab ASUSTeK Computer Inc, et see seade vastab
asjakohaste direktiivide oluliste nõuetele ja teistele asjassepuutuvatele
sätetele. EL vastavusdeklaratsiooni täielik tekst on saadaval järgmisel
aadressil: www.asus.com/support
Suomi ASUSTeK Computer Inc. ilmoittaa täten, että tämä laite on
asiaankuuluvien direktiivien olennaisten vaatimusten ja muiden tätä
koskevien säädösten mukainen. EU-yhdenmukaisuusilmoituksen koko teksti
on luettavissa osoitteessa: www.asus.com/support
Ελληνικά Με το παρόν, η AsusTek Computer Inc. δηλώνει ότι αυτή
η συσκευή συμμορφώνεται με τις θεμελιώδεις απαιτήσεις και άλλες
σχετικές διατάξεις των Οδηγιών της ΕΕ. Το πλήρες κείμενο της δήλωσης
συμβατότητας είναι διαθέσιμο στη διεύθυνση: www.asus.com/support
Magyar Az ASUSTeK Computer Inc. ezennel kijelenti, hogy ez az eszköz
megfelel a kapcsolódó Irányelvek lényeges követelményeinek és egyéb
vonatkozó rendelkezéseinek. Az EU megfelelőségi nyilatkozat teljes szövege
innen letölthető: www.asus.com/support
Latviski ASUSTeK Computer Inc. ar šo paziņo, ka šī ierīce atbilst saistīto
Direktīvu būtiskajām prasībām un citiem citiem saistošajiem nosacījumiem.
Pilns ES atbilstības paziņojuma teksts pieejams šeit: www.asus.com/support
Lietuvių „ASUSTeK Computer Inc.“ šiuo tvirtina, kad šis įrenginys atitinka
pagrindinius reikalavimus ir kitas svarbias susijusių direktyvų nuostatas. Visą
ES atitikties deklaracijos tekstą galima rasti: www.asus.com/support
Norsk ASUSTeK Computer Inc. erklærer herved at denne enheten er i
samsvar med hovedsaklige krav og andre relevante forskrifter i relaterte
direktiver. Fullstendig tekst for EU-samsvarserklæringen nnes på:
www.asus.com/support
Polski Firma ASUSTeK Computer Inc. niniejszym oświadcza, że
urządzenie to jest zgodne z zasadniczymi wymogami i innymi właściwymi
postanowieniami powiązanych dyrektyw. Pełny tekst deklaracji zgodności
UE jest dostępny pod adresem: www.asus.com/support
Português A ASUSTeK Computer Inc. declara que este dispositivo está em
conformidade com os requisitos essenciais e outras disposições relevantes
das Diretivas relacionadas. Texto integral da declaração da UE disponível em:
www.asus.com/support
ASUS PRIME B550M-K A-5
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
Web site https://www.asus.com
Technical Support
Telephone +86-21-38429911
Online support 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
Web site 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
Web site 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
A-6 Appendices