ASROCK X299 Steel Legend User manual

Version 1.0
Published October 2019
Copyright©2019 ASRock INC. All rights reserved.
Copyright Notice:
No part of this documentation may be reproduced, transcribed, transmitted, or
translated in any language, in any form or by any means, except duplication of
documentation by the purchaser for backup purpose, without written consent of
ASRock Inc.
Products and corporate names appearing in this documentation 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.
Disclaimer:
Specications and information contained in this documentation are furnished for
informational use only and subject to change without notice, and should not be
constructed as a commitment by ASRock. ASRock assumes no responsibility for
any errors or omissions that may appear in this documentation.
With respect to the contents of this documentation, ASRock does not provide
warranty of any kind, either expressed or implied, including but not limited to
the implied warranties or conditions of merchantability or tness for a particular
purpose.
In no event shall ASRock, its directors, ocers, employees, or agents be liable for
any indirect, special, incidental, or consequential damages (including damages for
loss of prots, loss of business, loss of data, interruption of business and the like),
even if ASRock has been advised of the possibility of such damages arising from any
defect or error in the documentation or product.
is 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.
CALIFORNIA, USA ONLY
e Lithium battery adopted on this motherboard contains Perchlorate, a toxic substance
controlled in Perchlorate Best Management Practices (BMP) regulations passed by the
California Legislature. When you discard the Lithium battery in California, USA, please
follow the related regulations in advance.
“Perchlorate Material-special handling may apply, see www.dtsc.ca.gov/hazardouswaste/
perchlorate”
ASRock Website: http://www.asrock.com

AUSTRALIA ONLY
Our goods come with guarantees that cannot be excluded under the Australian Consumer
Law. You are entitled to a replacement or refund for a major failure and compensation for
any other reasonably foreseeable loss or damage caused by our goods. You are also entitled
to have the goods repaired or replaced if the goods fail to be of acceptable quality and the
failure does not amount to a major failure. If you require assistance please call ASRock Tel
: [phone] ext.123 (Standard International call charges apply)

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X299 Steel Legend
Motherboard Layout
ATXPWR1
Intel
X299
ATX12V1
LAN
LAN
PCIE1
Top:
Central/Bass
Center:
REAR SPK
Top:
LIN E IN
Center:
FRONT
Bottom:
Optical
SPDIF
Bottom:
MIC I N
PCIE3
USB_7_8
1
1
USB_5_6
1
HD_AUDIO1
PCIE5
SATA3_2_3
SATA3_4_5
PCIE4
CPU_FAN1
12
16
17
18
SATA3_6_7
19
28 2733
CLRC
BTN1
SATA3_0_1
359
DDR4_B2 (64 bit, 288-pin module)
DDR4_B1 (64 bit, 288-pin module)
DDR4_A2 (64 bit, 288-pin module)
DDR4_A1 (64 bit, 288-pin module)
2
1
29 23
32
DDR4_C1 (64 bit, 288-pin module)
DDR4_C2 (64 bit, 288-pin module)
DDR4_D1 (64 bit, 288-pin module)
DDR4_D2 (64 bit, 288-pin module)
7
6
2066 Socket
1
SPK_PLED1
20
1
USB3_4_5
15
21
22
T B1
1
RGB_HEADER1
1
RGB_HEADER2
1
30
PCIE2
Purity
Sound 4
TM
ADDR_LED1
1
ADDR_LED2
1
VROC1
1
ATX12V2
4
CPU_FAN2
/WP
CHA_FAN3
/WP
CHA_FAN1
/WP
CHA_FAN2
/WP
13
34
F_USB_3_TC1
1
SPI_TPM_J1
HDLED RESET
PLED PWRBTN
PANEL1
1
26 24
CHA_FAN4
/WP
25
CHA_FAN5
/WP
31
USB 2.0
T: USB3
B: USB4
USB 3.2 Gen1
T: USB1
B: USB2
Top:
RJ-45
(I219V )
Top:
RJ-45
I211AT
8
10
BOOT
VGA
DRAM
CPU
11
BIOS
ROM
CLRMOS1
1
14
CMOS
Battery
M2_1
CT2
CT3
CT4
CT5
CT1
CT3
M2_2
CT4
M2_WIFI_1
USB 3.2 Gen1
T: USB3_3
USB 3.2 Gen2x2
B: USB31_TC_1
USB 2.0
T: USB1
B: USB2
PS2
Keyboard
/Mouse

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No. Description
1 2 x 288-pin DDR4 DIMM Slots (DDR4_A1, DDR4_B1)
2 2 x 288-pin DDR4 DIMM Slots (DDR4_A2, DDR4_B2)
3 ATX 12V Power Connector (ATX12V1)
4 ATX 12V Power Connector (ATX12V2)
5 CPU Fan Connector (CPU_FAN1)
6 2 x 288-pin DDR4 DIMM Slots (DDR4_C2, DDR4_D2)
7 2 x 288-pin DDR4 DIMM Slots (DDR4_C1, DDR4_D1)
8 CPU / Waterpump Fan Connector (CPU_FAN2/WP)
9 RGB LED Header (RGB_HEADER2)
10 Addressable LED Header (ADDR_LED2)
11 Post Status Checker (PSC)
12 ATX Power Connector (ATXPWR1)
13 Front Panel Type C USB 3.2 Gen2 Header (F_USB_3_TC1)
14 Virtual RAID On CPU Header (VROC1)
15 USB 3.2 Gen1 Header (USB3_4_5)
16 SATA3 Connectors (SATA3_0_1)
17 SATA3 Connectors (SATA3_2_3)
18 SATA3 Connectors (SATA3_4_5)
19 SATA3 Connectors (SATA3_6_7)
20 Chassis / Waterpump Fan Connector (CHA_FAN2/WP)
21 SPI TPM Header (SPI_TPM_J1)
22 Power LED and Speaker Header (SPK_PLED1)
23 System Panel Header (PANEL1)
24 Chassis / Waterpump Fan Connector (CHA_FAN3/WP)
25 Chassis / Waterpump Fan Connector (CHA_FAN4/WP)
26 Clear CMOS Jumper (CLRMOS1)
27 USB 2.0 Header (USB_7_8)
28 USB 2.0 Header (USB_5_6)
29 Addressable LED Header (ADDR_LED1)
30 RGB LED Header (RGB_HEADER1)
31 Chassis / Waterpump Fan Connector (CHA_FAN5/WP)
32 underbolt AIC Connector (TB1)
33 Front Panel Audio Header (HD_AUDIO1)
34 Chassis / Waterpump Fan Connector (CHA_FAN1/WP)

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X299 Steel Legend
I/O Panel
No. Description No. Description
1 USB 2.0 Port (USB_12) 10 USB 3.2 Gen1 Port (USB3_3)
2 LAN RJ-45 Port (Intel® I219V)* 11 USB 3.2 Gen2x2 Type-C Port
3 LAN RJ-45 Port (Intel® I211AT)* (USB31_TC_1)
4 Central / Bass (Orange) 12 USB 3.2 Gen1 Ports (USB3_12)
5 Rear Speaker (Black) 13 USB 2.0 Port (USB_34)
6 Line In (Light Blue) 14 Clear CMOS Button
7 Front Speaker (Lime)** 15 Antenna Bracket (on I/O Panel Shield)
8Microphone (Pink) 16 PS/2 Mouse/Keyboard Port
9 Optical SPDIF Out Port
* ere are two LEDs on each LAN port. Please refer to the table below for the LAN port LED indications.
Activity / Link LED Speed LED
Status Description Status Description
O No Link O 10Mbps connection
Blinking Data Activity Orange 100Mbps connection
On Link Green 1Gbps connection
ACT/LINK LED
SPEED LED
LAN Port
1
16 131415
2
89
5
4
7
6
12
3
10
11

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**If you use a 2-channel speaker, please connect the speaker’s plug into “Front Speaker Jack”. See the table below
for connection details in accordance with the type of speaker you use.
Audio Output
Channels
Front Speaker
(No. 7)
Rear Speaker
(No. 5)
Central / Bass
(No. 4)
Line In
(No. 6)
2V -- -- --
4V V -- --
6V V V --
8VVVV
Chapter 1 Introduction
ank you for purchasing ASRock X299 Steel Legend motherboard, a reliable
motherboard produced under ASRock’s consistently stringent quality control.
It delivers excellent performance with robust design conforming to ASRock’s
commitment to quality and endurance.
1.1 Package Contents
• ASRock X299 Steel Legend Motherboard (ATX Form Factor)
• ASRock X299 Steel Legend Quick Installation Guide
• ASRock X299 Steel Legend Support CD
• 1 x I/O Panel Shield
• 1 x ASRock SLI_HB_Bridge_2S Card (Optional)
• 4 x Serial ATA (SATA) Data Cables (Optional)
• 3 x Screws for M.2 Sockets (Optional)
• 2 x Standos for M.2 Sockets (Optional)

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X299 Steel Legend
Chapter 1 Introduction
ank you for purchasing ASRock X299 Steel Legend motherboard, a reliable
motherboard produced under ASRock’s consistently stringent quality control.
It delivers excellent performance with robust design conforming to ASRock’s
commitment to quality and endurance.
1.1 Package Contents
• ASRock X299 Steel Legend Motherboard (ATX Form Factor)
• ASRock X299 Steel Legend Quick Installation Guide
• ASRock X299 Steel Legend Support CD
• 1 x I/O Panel Shield
• 1 x ASRock SLI_HB_Bridge_2S Card (Optional)
• 4 x Serial ATA (SATA) Data Cables (Optional)
• 3 x Screws for M.2 Sockets (Optional)
• 2 x Standos for M.2 Sockets (Optional)
Because the motherboard specications and the BIOS soware might be updated, the
content of this documentation will be subject to change without notice. In case any modi-
cations of this documentation occur, the updated version will be available on ASRock’s
website without further notice. If you require technical support related to this mother-
board, please visit our website for specic information about the model you are using. You
may nd the latest VGA cards and CPU support list on ASRock’s website as well. ASRock
website http://www.asrock.com.

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1.2 Specications
Platform • ATX Form Factor
CPU • Supports Intel® CoreTM X-Series Processor Family for the
LGA 2066 Socket (Cascade Lake-X, Skylake X Refresh and
Skylake X)
• Digi Power design
• 11 Power Phase design
• Supports Intel® Turbo Boost Max Technology 3.0
Chipset • Intel® X299
Memory • Quad Channel DDR4 Memory Technology
• 8 x DDR4 DIMM Slots
• Supports DDR4 4200+(OC)*/4000(OC)/3800(OC)/3733
(OC)/3600(OC)/3200(OC)/2933(OC)/2800(OC)/
2666/2400/2133 non-ECC, un-buered memory
* e maximum memory frequency supported may vary by
processor type.
* Please refer to Memory Support List on ASRock’s website for
more information. (http://www.asrock.com/)
• Max. capacity of system memory: 256GB
• Supports Intel® Extreme Memory Prole (XMP) 2.0
• 15μ Gold Contact in DIMM Slots
Expansion
Slot
• 4 x PCI Express 3.0 x16 Slots*
* If you install CPU with 48 lanes, PCIE1/PCIE2/PCIE3/PCIE5
will run at x16/x4/x16/x8.
* If you install CPU with 44 lanes, PCIE1/PCIE2/PCIE3/PCIE5
will run at x16/x4/x16/x8.
* If you install CPU with 28 lanes, PCIE1/PCIE2/PCIE3/PCIE5
will run at x16/x4/x8/x0.
• 1 x PCI Express 3.0 x1 Slot**
• Supports AMD 3-Way CrossFireXTM and CrossFireXTM**
• Supports NVIDIA® 3-Way SLITM and SLITM**
** 3-Way CrossFireXTM and 3-Way SLITM are only supported
with CPU with 48 lanes or 44 lanes.

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X299 Steel Legend
• 1 x M.2 Socket (Key E), supports type 2230 WiFi/BT module
• 15μ Gold Contact in VGA PCIe Slot (PCIE1 and PCIE3)
Audio • 7.1 CH HD Audio with Content Protection (Realtek
ALC1220 Audio Codec)
• Premium Blu-ray Audio support
• Supports Surge Protection (ASRock Full Spike Protection)
• Supports Purity SoundTM 4
- Nichicon Fine Gold Series Audio Caps
- 120dB SNR DAC with Dierential Amplier
- NE5532 Premium Headset Amplier for Front Panel
Audio Connector (Supports up to 600 Ohm headsets)
- Pure Power-In
- Direct Drive Technology
- PCB Isolate Shielding
- Impedance Sensing on Rear Out port
- Individual PCB Layers for R/L Audio Channel
- Gold Audio Jacks
- 15μ Gold Audio Connector
LAN • Gigabit LAN 10/100/1000 Mb/s
• 1 x Giga PHY Intel® I219V, 1 x GigaLAN Intel® I211AT
• Supports Wake-On-LAN
• Supports Lightning/ESD Protection
• Supports Dual LAN with Teaming*
* Teaming is supported on Windows® 10 RS2, RS3 and RS4.
• Supports Energy Ecient Ethernet 802.3az
• Supports PXE
Rear Panel
I/O
• 2 x Antenna Ports (on I/O Panel Shield)
• 1 x PS/2 Mouse/Keyboard Port
• 1 x Optical SPDIF Out Port
• 4 x USB 2.0 Ports (Supports ESD Protection)
• 1 x USB 3.2 Gen2x2 Type-C Port (20 Gb/s) (ASMedia
ASM3242) (Supports ESD Protection)
• 3 x USB 3.2 Gen1 Ports (Supports ESD Protection)
• 2 x RJ-45 LAN Ports with LED (ACT/LINK LED and SPEED
LED)
• 1 x Clear CMOS Button

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• HD Audio Jacks: Rear Speaker / Central / Bass / Line in /
Front Speaker / Microphone (Gold Audio Jacks)
Storage • 8 x SATA3 6.0 Gb/s Connectors, support RAID (RAID 0,
RAID 1, RAID 5, RAID 10, Intel Rapid Storage Technology
17 and Intel Smart Response Technology), NCQ, AHCI and
Hot Plug*
* If M2_1 is occupied by a SATA-type M.2 device, SATA3_1 will
be disabled.
* If M2_2 is occupied by a SATA-type M.2 device, SATA3_0 will
be disabled.
• 1 x Ultra M.2 Socket (M2_1), supports M Key type
2230/2242/2260/2280/22110 M.2 SATA3 6.0 Gb/s module
and M.2 PCI Express module up to Gen3 x4 (32 Gb/s)**
• 1 x Ultra M.2 Socket (M2_2), supports M Key type
2260/2280 M.2 SATA3 6.0 Gb/s module and M.2 PCI Ex-
press module up to Gen3 x4 (32 Gb/s)**
** Supports Intel® OptaneTM Technology
** Supports PCIe RAID
** Supports NVMe SSD as boot disks
Connector • 1 x Virtual RAID On CPU Header
• 1 x SPI TPM Header
• 1 x Power LED and Speaker Header
• 2 x RGB LED Headers
* Supports in total up to 12V/3A, 36W LED Strip
• 2 x Addressable LED Headers
* Support in total up to 5V/3A, 15W LED Strip
• 1 x CPU Fan Connector (4-pin)
* e CPU Fan Connector supports the CPU fan of maximum
1A (12W) fan power.
• 1 x CPU/Water Pump Fan Connector (4-pin) (Smart Fan
Speed Control)
* e CPU/Water Pump Fan supports the water cooler fan of
maximum 2A (24W) fan power.
• 5 x Chassis/Water Pump Fan Connectors (4-pin) (Smart Fan
Speed Control)
* e Chassis/Water Pump Fan supports the water cooler fan of
maximum 2A (24W) fan power.

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X299 Steel Legend
* CPU_FAN2/WP, CHA_FAN1~5/WP can auto detect if 3-pin
or 4-pin fan is in use.
• 1 x 24 pin ATX Power Connector (Hi-Density Power
Connector)
• 2 x 8 pin 12V Power Connectors (Hi-Density Power
Connector)
• 1 x Front Panel Audio Connector (15μ Gold Audio
Connector)
• 1 x underbolt AIC Connector (5-pin)
* e underbolt™ AIC card can be installed in the enabled
PCIe slot (depending on CPU type).
• 2 x USB 2.0 Headers (Support 4 USB 2.0 ports) (Supports
ESD Protection)
• 1 x USB 3.2 Gen1 Header (Supports 2 USB 3.2 Gen1 ports)
(Supports ESD Protection)
• 1 x Front Panel Type C USB 3.2 Gen1 Header (ASMedia
ASM1074 Hub)
BIOS
Feature
• AMI UEFI Legal BIOS with multilingual GUI support
• ACPI 6.1 Compliant wake up events
• SMBIOS 3.0 Support
• CPU, DRAM, VPPM, VTTM, PCH 1.0V, VCCIO,
VCCSA,Voltage Multi-adjustment
Hardware
Monitor
• Temperature Sensing: CPU, CPU/Water Pump, Chassis/
Water Pump Fans
• Fan Tachometer: CPU, CPU/Water Pump, Chassis/Water
Pump Fans
• Quiet Fan (Auto adjust chassis fan speed by CPU tempera-
ture): CPU, CPU/Water Pump, Chassis/Water Pump Fans
• Fan Multi-Speed Control: CPU, CPU/Water Pump, Chassis/
Water Pump Fans
• Voltage monitoring: +12V, +5V, +3.3V, CPU Vcore, DRAM,
PCH 1.0V, VCCIO, VCCSA
OS • Microso® Windows® 10 64-bit
Certica-
tions
• FCC, CE
• ErP/EuP ready (ErP/EuP ready power supply is required)

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Please realize that there is a certain risk involved with overclocking, including adjusting
the setting in the BIOS, applying Untied Overclocking Technology, or using third-party
overclocking tools. Overclocking may aect your system’s stability, or even cause damage to
the components and devices of your system. It should be done at your own risk and expense.
We are not responsible for possible damage caused by overclocking.
* For detailed product information, please visit our website: http://www.asrock.com

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11
X299 Steel Legend
is is an ATX form factor motherboard. Before you install the motherboard, study
the conguration of your chassis to ensure that the motherboard ts into it.
Pre-installation Precautions
Take note of the following precautions before you install motherboard components
or change any motherboard settings.
• Make sure to unplug the power cord before installing or removing the motherboard
components. Failure to do so may cause physical injuries and damages to motherboard
components.
• In order to avoid damage from static electricity to the motherboard’s components,
NEVER place your motherboard directly on a carpet. Also remember to use a grounded
wrist strap or touch a safety grounded object before you handle the components.
• Hold components by the edges and do not touch the ICs.
• Whenever you uninstall any components, place them on a grounded anti-static pad or
in the bag that comes with the components.
• When placing screws to secure the motherboard to the chassis, please do not over-
tighten the screws! Doing so may damage the motherboard.
Chapter 2 Installation

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12
2.1 Installing the CPU
CAUTION:
Please note that X299 platform is only compatible with the LGA 2066 socket, which is
incompatible with the LGA 2011-3 socket (for X99 platform).
1. Before you insert the 2066-Pin CPU into the socket, please check if the PnP cap is on the
socket, if the CPU surface is unclean, or if there are any bent pins in the socket. Do not
force to insert the CPU into the socket if above situation is found. Otherwise, the CPU
will be seriously damaged.
2. Unplug all power cables before installing the CPU.
A
B
A
B
1
2

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13
X299 Steel Legend
4
A
3
B
5

English
14
Please save and replace the cover if the processor is removed. e cover must be placed if
you wish to return the motherboard for aer service.
6
A
B
8
B
7
A

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X299 Steel Legend
2.2 Installing the CPU Fan and Heatsink
CPU_FAN
1 2

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16
2.3 Installation of Memory Modules (DIMM)
is motherboard provides eight 288-pin DDR4 (Double Data Rate 4) DIMM slots, and
supports Quad Channel Memory Technology.
Quad Channel Memory Conguration (For CPU with 48, 44 or 28 PCIe
lanes)
Priority 1 2
DDR4_B1 Populated Populated
DDR4_B2 Populated
DDR4_A1 Populated Populated
DDR4_A2 Populated
DDR4_D1 Populated Populated
DDR4_D2 Populated
DDR4_C1 Populated Populated
DDR4_C2 Populated
• Due to Intel® CPU spec denition, please install the memory modules on DDR4_A1,
DDR4_B1, DDR4_C1 and DDR4_D1 for rst priority. If the four DDR4 DIMM slots
above are fully installed, and you want to use more than four memory modules, please
install the other memory modules from le to right (from DDR4_A2, DDR4_B2,
DDR4_D2 to DDR4_C2.)
• If only two memory modules are installed in the DDR4 DIMM slots, then Dual
Channel Memory Technology is activated. If three memory modules are installed, then
Triple Channel Memory Technology is activated. If more than four memory modules
are installed in the DDR4 DIMM slots, then Quad Channel Memory Technology is
activated.
1. For quad channel conguration, you always need to install identical (the same brand,
speed, size and chip-type) DDR4 DIMM pairs.
2. It is not allowed to install a DDR, DDR2 or DDR3 memory module into a DDR4 slot;
otherwise, this motherboard and DIMM may be damaged.
3. e DIMM only ts in one correct orientation. It will cause permanent damage to the
motherboard and the DIMM if you force the DIMM into the slot at incorrect orientation.

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X299 Steel Legend
1
2
3

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18
2.4 Expansion Slots (PCI Express Slots)
ere are 5 PCI Express slots on the motherboard.
PCIe slots:
PCIE1 (PCIe 3.0 x16 slot) is used for PCI Express x16 lane width graphics cards.
PCIE2 (PCIe 3.0 x16 slot) is used for PCI Express x4 lane width graphics cards.
PCIE3 (PCIe 3.0 x16 slot) is used for PCI Express x16 lane width graphics cards.
PCIE4 (PCIe 3.0 x1 slot) is used for PCI Express x1 lane width cards.
PCIE5 (PCIe 3.0 x16 slot) is used for PCI Express x8 lane width graphics cards.
* If you install CPU with 48 lanes, PCIE1/PCIE2/PCIE3/PCIE5 will run at x16/x4/
x16/x8.
* If you install CPU with 44 lanes, PCIE1/PCIE2/PCIE3/PCIE5 will run at x16/x4/
x16/x8.
* If you install CPU with 28 lanes, PCIE1/PCIE2/PCIE3/PCIE5 will run at x16/x4/
x8/x0.
PCIe Slot Congurations (For CPU with 48 PCIe lanes)
Before installing an expansion card, please make sure that the power supply is switched o
or the power cord is unplugged. Please read the documentation of the expansion card and
make necessary hardware settings for the card before you start the installation.
PCIE1 PCIE2 PCIE3 PCIE5
Single Graphics Card x16 N/A N/A N/A
Two Graphics Cards in
CrossFireXTM or SLITM
Mode
x16 N/A x16 N/A
ree Graphics Cards in
3-Way CrossFireXTM Mode
or 3-Way SLITM Mode
x16 N/A x16 x8