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
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 identication or explanation and to the
owners’ benet, without intent to infringe.
Offer to Provide Source Code of Certain Software
This product may contain copyrighted software that is licensed under the General Public License (“GPL”)
and under the Lesser General Public License Version (“LGPL”). The GPL and LGPL licensed code in this
product is distributed without any warranty. Copies of these licenses are included in this product.
You may obtain the complete corresponding source code (as dened in the GPL) for the GPL Software,
and/or the complete corresponding source code of the LGPL Software (with the complete machinereadable “work that uses the Library”) for a period of three years after our last shipment of the product
including the GPL Software and/or LGPL Software, which will be no earlier than December 1, 2011, either
(1) for free by downloading it from http://support.asus.com/download;
or
(2) for the cost of reproduction and shipment, which is dependent on the preferred carrier and the location
where you want to have it shipped to, by sending a request to:
ASUSTeK Computer Inc.
Legal Compliance Dept.
15 Li Te Rd.,
Beitou, Taipei 112
Taiwan
In your request please provide the name, model number and version, as stated in the About Box of the
product for which you wish to obtain the corresponding source code and your contact details so that we
can coordinate the terms and cost of shipment with you.
The source code will be distributed WITHOUT ANY WARRANTY and licensed under the same license as
the corresponding binary/object code.
This offer is valid to anyone in receipt of this information.
ASUSTeK is eager to duly provide complete source code as required under various Free Open Source
Software licenses. If however you encounter any problems in obtaining the full corresponding source code
we would be much obliged if you give us a notication to the email address gpl@asus.com, stating the
product and describing the problem (please do NOT send large attachments such as source code archives
etc to this email address).
5.2.2 Installing two SLI-ready graphics cards ...................................... 5-4
5.2.3 Installing the device drivers ......................................................... 5-5
5.2.4 Enabling the NVIDIA® SLI™ technology ..................................... 5-5
v
Notices
Federal Communications Commission Statement
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two
conditions:
• This device may not cause harmful interference, and
• 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 manufacturer’s 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 to 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.
The use of shielded cables for connection of the monitor to the graphics card is required
to assure compliance with FCC regulations. Changes or modications to this unit not
expressly approved by the party responsible for compliance could void the user’s authority
to operate this equipment.
Canadian Department of Communications Statement
This digital apparatus does not exceed the Class B limits for radio noise emissions from
digital apparatus set out in the Radio Interference Regulations of the Canadian Department
of Communications.
This class B digital apparatus complies with Canadian ICES-003.
REACH
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.
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.
vi
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 devices on it, 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 qualied service
technician or your retailer.
vii
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.
• Chapter 2: Hardware information
This chapter lists the hardware setup procedures that you have to perform when
installing system components. It includes description of the switches, jumpers, and
connectors on the motherboard.
• Chapter 3: BIOS setup
This chapter tells how to change system settings through the BIOS Setup menus.
Detailed descriptions of the BIOS parameters are also provided.
• Chapter 4: Software support
This chapter describes the contents of the support DVD that comes with the
motherboard package and the software.
• Chapter 5: Multiple GPU technology support
This chapter describes how to install and congure multiple ATI® CrossFireX™ and
NVIDIA® SLI™ graphics cards.
Where to nd more information
Refer to the following sources for additional information and for product and software
updates.
1. ASUS websites
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 yers,
that may have been added by your dealer. These documents are not part of the
standard package.
viii
Conventions used in this guide
To ensure that you perform certain tasks properly, take note of the following symbols used
throughout this manual.
DANGER/WARNING: Information to prevent injury to yourself when trying to
CAUTION: Information to prevent damage to the components when trying to
IMPORTANT: Instructions that you MUST follow to complete a task.
NOTE: Tips and additional information to help you complete a task.
complete a task.
complete a task.
Typography
Bold textIndicates a menu or an item to select.
ItalicsUsed to emphasize a word or a phrase.
<Key>Keys enclosed in the less-than and greater-than sign means
<Key1> + <Key2> + <Key3> If you must press two or more keys simultaneously, the key
that you must press the enclosed key.
Example: <Enter> means that you must press the Enter or
Return key.
names are linked with a plus sign (+).
Example: <Ctrl> + <Alt> + <Del>
ix
SABERTOOTH 990FX specications summary
CPUAMD® socket AM3+ for AMD® FX Series CPU up to 8-core
ChipsetAMD® 990FX/SB950
System BusUp to 5.2 GT/s HyperTransport™ 3.0
Memory*4 x DIMM, Max. 32GB, DDR3 1866/1600/1333/1066 MHz, ECC, Non-
Multi-GPU TechnologySupport NVIDIA® Quad-GPU SLI™ and ATI® Quad-GPU CrossFireX™
StorageAMD® SB950 Chipset:
LANRealtek® 8111E Gigabit LAN controller
High Denition AudioRealtek® ALC892 8-channel High Denition Audio CODEC
IEEE 1394VIA® VT6308P controller supports 2 x IEEE 1394a ports (1 port at mid-
Compatible with AMD® socket AM3 for AMD® Phenom™ II/
Athlon™ II/Sempron™ 100 Series Processors
Supports 32nm CPU
AMD® Cool 'n' Quiet™ Technology
AMD® 140W CPU Support
ECC and un-buffered memory
Dual channel memory architecture
* Refer to www.asus.com or user manual for the Memory QVL (Qualied
Vendors Lists) of AM3+ / AM3 CPU
** Due to OS limitation, when installing total memory of 4GB capacity
or more, Windows® 32-bit operation system may only recognize
less than 3GB. Hence, a total installed memory of less than 3GB is
recommended.
*** Due to CPU spec, AMD 100 Series CPUs support up to DDR3
1066MHz. With ASUS design, this mptherboard can support up to
DDR3 1333MHz.
x16 / x8 / x8 mode)*
1 x PCI Express 2.0 x16 slot (Black @ x4)
1 x PCI Express 2.0 x1 slot
1 x PCI slot
* In dual VGA card mode, ensure to install the VGA cards to PCIex16_1
and PCIex16_3 for better performance. Refer to “2.5 Expansion slots”
for details.
Technology
- 6 x SATA 6Gb/s ports with RAID 0, 1, 5, 10 support
ASUS UEFI BIOS EZ Mode featuring friendly graphics user
interface
AI Suite II
ASUS Q-Connector
ASUS Q-Shield
ASUS Q-LED (CPU, DRAM, VGA, Boot Device LED)
ASUS Q-Slot
ASUS Q-DIMM
ASUS O.C. Prole
ASUS EZ Flash 2
ASUS MyLogo 2
Multi-language BIOS
2.5, ACPI 2.0a, Multi-language BIOS, ASUS EZ Flash 2
(continued on the next page)
xi
SABERTOOTH 990FX specications summary
ManageabilityWfM 2.0, DMI 2.0, WOL by PME, WOR by PME, PXE
Back Panel I/O Ports1 x PS/2 Keyboard/Mouse combo port
Internal I/O Connectors1 x USB 3.0/2.0 connector supports additional 2 USB 3.0/2.0 ports
SoftwareDrivers
Form FactorATX Form Factor, 12”x 9.6” (30.5cm x 24.4cm)
1 x Optical S/PDIF Output port
1 x Power eSATA 3Gb/s port (green)
1 x eSATA 3Gb/s port (red)
1 x IEEE1394a port
1 x LAN (RJ45) port
2 x USB 3.0/2.0 ports (blue)
10 x USB 2.0/1.1 ports
8-channel Audio I/O ports
(19-pin; moss green)
2 x USB 2.0/1.1 connectors support additional 4 USB 2.0/1.1 ports
6 x SATA 6Gb/s connectors (brown)
2 x SATA 3Gb/s connectors (black)
1 x CPU Fan connector (4-pin)
4 x Chassis Fan connectors (3 x 4-pin; 1 x 3-pin)
1 x CPU Opt fan connector (4-pin)
1 x IEEE1394a connector
Front panel audio connector
1 x COM connector
1 x S/PDIF Out header
24-pin EATX Power connector
8-pin EATX 12V Power connector
System Panel (Q-Connector)
1 x MemOK! button
1 x Clear CMOS jumper
Anti-virus software (OEM version)
ASUS Update
ASUS Utilities
*Specications are subject to change without notice.
xii
Chapter 1
User Manual
Five-year warranty
1.1 Welcome!
Thank you for buying an ASUS® SABERTOOTH 990FX motherboard!
The motherboard delivers a host of new features and latest technologies, making it another
standout in the long line of ASUS quality motherboards!
Before you start installing the motherboard, and hardware devices on it, check the items in
your package with the list below.
1.2 Package contents
Check your motherboard package for the following items.
ASUS SABERTOOTH 990FX
motherboard
4 x Serial ATA 6.0 Gb/s cables
1 x ASUS Q-Shield1 x 2-in-1 ASUS Q-Connector kit
User guideSupport DVD
1 x ASUS SLI™ bridge
connector
Chapter 1
1 x TUF Certication card
1 x TUF Five-year warranty
manual
ASUS SABERTOOTH 990FX1-1
• If any of the above items is damaged or missing, contact your retailer.
• The illustrated items above are for reference only. Actual product specications may
vary with different models.
1.3 Special features
1.3.1 Product highlights
Chapter 1
The Ultimate Force
TUF /tΛf/, stands for The Ultimate Force.
The TUF series delivers a “tough” image. With the unique design & high quality components
(military-standard), TUF series is born for pursuing the preeminent stability, all-round
compatibility, and extreme durability
This motherboard supports latest AMD® Socket AM3+ multi-core processors with up to 8-core
native CPU cores and delivers better overclocking capabilities with less power consumption.
It features AMD Turbo CORE Technology 2.0 and accelerates data transfer rate up to
5200MT/s via HyperTransport™ 3.0 based system bus. This motherboard also supports
AMD® CPUs in the new 32nm manufacturing process.
AMD 990FX Chipset
AMD 990FX Chipset is designed to support up to 5.2GT/s HyperTransport™ 3.0 (HT 3.0)
interface speed and dual PCI Express™ 2.0 x16 graphics. It is optimized with AMD latest
AM3+ and multi-core CPUs to provide excellent system performance and overclocking
capabilities.
Quad-GPU SLI and Quad-GPU CrossFireX™ support!
Flexible Multi-GPU Solutions, Your Weapon of Choice!
SABERTOOTH 990FX brings multi-GPU congurations through both SLI™ and CrossFireX.
This motherboard features the powerful AMD® 990FX chipset, optimizing PCIe allocation in
multiple GPU setups. Expect a brand new gaming sensation like you’ve never experienced
before!
PCIe 2.0
Double Speed; Double Bandwidth
This motherboard supports the latest PCIe 2.0 devices for double speed and bandwidth
which enhances system performance.
Front Panel USB 3.0 Support
Convenient USB 3.0 Front Panel Compatibility
ASUS provides standardized USB 3.0 front panel support, compatible with any chassis.
Enjoy faster throughput of USB 3.0 without relegating cables or devices to the hard-to-reach
rear I/O.
Complete USB 3.0 Solution
Double USB access, double convenience
ASUS facilitates strategic USB 3.0 accessibility for both the front and rear panel - 4 USB
3.0 ports in total. Experience the latest plug & play connectivity at speeds up to 10 times
faster than USB 2.0. The SABERTOOTH 990FX affords greater convenience to high speed
connectivity.
1-2Chapter 1: Product Introduction
1.3.2 “Ultimate COOL!” Thermal Solution
TUF CeraM!X - Heatsink Coating Tech.
Larger area for heat dissipation with the revolutionary ceramics-coating technology
Innovative ceramics actively conducts heat away from the system. It replaces traditional
anti-oxidant to dissipate heat better with its microscopic irregular surface and enlarged area.
Better cooling leads to overall improvement in system stability.
Do Not uninstall the heatsink module by youself. Doing so may bend the tubing and affect
the heat dissipation performance.
TUF Thermal Radar
Real Time Temp Detection and Heat Removal
The TUF Thermal Radar monitors temps in critical parts of the motherboard in real time,
automatically adjusting fan speeds to make sure the system maintains high stability without
overheating. It consists of multiple sensors for various components on the motherboard,
giving users the ability to monitor each one individually. The Thermal Radar automatically
calculates ideal fan speeds based on different parameters selected by users for each
component, keeping everything cooler and longer lasting.
1.3.3 “TUF ENGINE!” Power Design
DIGI+ VRM
Herald the Arrival of a New Digital Power Design Era
The new ASUS DIGI+ VRM design upgrades motherboard power delivery to a digital
standard. The 8+2 digital architecture provides the highest power efciency, generating
less heat to enhance longer component lifespan and ensure minimal powerloss. With ASUS
DIGI+ VRM, users can easily adjust power phase performance, enabling new PWM voltage
and frequency modulation controls. Digital 8+2 power phase design also expands the
modulation spectrum for improved stability and lower VRM switching noise by dynamically
detecting system load, empowering users with superior exibility and perfect precision to
ensure optimized performance, extreme system stability, and greater power efciency.
E.S.P. Efcient Switching Power Design
Optimal power efciency for key components
Exclusively for this motherboard, the switching power design is provided not only for the CPU
and memory, but also for other key components such as graphics cards, LAN and USB 3.0.
E.S.P. dramatically improves system efciency and reduces heat generation.
Chapter 1
ASUS SABERTOOTH 990FX1-3
TUF Components (Alloy Choke, Cap. & MOSFET; Certied by Military-
standard)
Chapter 1
Certied for Tough Duty
Get rugged performance even in the most challenging conditions with robust TUF chokes,
solid capacitors, and MOSFETs--certied through third-party, military-grade testing. TUF
Chokes, also known as the “Alloy Choke”, is a made of a compound of various types of metal
instead standard iron, enables the support of up to a massive 40A of rated current, 25%
higher than conventional component. Furthermore, the single piece packaing also elimates
the emission of virbation noise, delivering superb charactoristics as well as durability under
extreme conditions.
ESD Guards
Unique protection of motherboard components from unexpected electrostatic
discharges (ESD)
Electrostatic discharge (ESD) can happen suddenly and its damaging effects is often
underestimated. Exclusive ASUS anti-static chip, a protective circuit design, and the I/O
shield provides four times better protection to extend component lifespan.
Any Memory is A-OK!
MemOK! quickly ensures memory boot compatibility. This remarkable memory rescue tool
requires a mere push of a button to patch memory issues. MemOK! determines failsafe
settings and dramatically improves system boot success. Get your system up and running in
no time!
1.3.4 ASUS DIY
UEFI BIOS (EZ Mode)
Flexible & Easy BIOS Interface
ASUS brand new UEFI BIOS offers a user-friendly interface that goes beyond traditional
keyboard only BIOS, to enable more exible and convenient mouse controls. Users can
easily navigate the new UEFI BIOS with the same smoothness as their operating system.
The exclusive EZ Mode displays frequently-accessed setup info, while the Advanced Mode is
for experienced performance enthusiasts that demand far more intricate system settings.
AI Suite II
One-stop Access to Innovative ASUS Features
With its user-friendly interface, ASUS AI Suite II consolidates all the exclusive ASUS features
into one simple to use software package. It allows you to supervise energy management, fan
speed control, voltage and sensor readings. This all-in-one software offers diverse and ease
to use functions, with no need to switch back and forth between different utilities.
1-4Chapter 1: Product Introduction
ASUS Q-Design
DIY quickly, DIY easily!
ASUS Q-Design enhances your DIY experience. All of Q-LED, Q-Slot, and Q-DIMM design
speed up and simplify the DIY process!
Q-Shield
Easy and Comfortable Installations
The specially designed ASUS Q-Shield does without the usual ""ngers"" - making it
convenient and easy to install. With better electric conductivity, it ideally protects your
motherboard against static electricity and shields it against Electronic Magnetic Interference
(EMI).
ASUS Q-Connector
Make connection quick and accurate!
The ASUS Q-Connector allows you to connect or disconnect chassis front panel cables
in one easy step with one complete module. This unique adapter eliminates the trouble of
plugging in one cable at a time, making connection quick and accurate.
EZ Flash2
Simply update BIOS from a USB ash disk before entering the OS
EZ Flash 2 is a user-friendly BIOS update utility. Simply launch this tool and update BIOS
from a USB ash disk before entering the OS. You can update your BIOS only in a few clicks
without preparing an additional oppy diskette or using an OS-based ash utility.
O.C. Prole
Conveniently store or load multiple BIOS settings
Freely share and distribute favorite overclocking settings The motherboard features the
ASUS O.C. Prole that allows users to conveniently store or load multiple BIOS settings. The
BIOS settings can be stored in the CMOS or a separate le, giving users freedom to share
and distribute their favorite overclocking settings.
sound, jack-sensing feature, retasking functions and multi-streaming technology.
MyLogo2
Personalize your system with customizable boot logo
The ASUS MyLogo 2 is the new feature present in the motherboard that allows you to
personalize and add style to your system with customizable and animated boot logos.
ASUS SABERTOOTH 990FX1-5
Power eSATA on the Go
The motherboard supports hard drives based on the Serial ATA (SATA) 3Gb/s storage
specication, delivering enhanced scalability and doubling the bus bandwidth for high-speed
Chapter 1
data retrieval and saves.The Power eSATA solution combines the eSATA connector and
power source together, allowing users to use external SATA devices without the need of
additional power source*. The external SATA port located at the back I/O provides smart
setup and hot-plug functions. Easily backup photos, videos and other entertainment contents
on external devices. *Power eSATA requires a specially designed signal cable to provide 5V
power for the external SATA device. The cable is purchased separately.
IEEE 1394a interface
IEEE 1394a interface provides high speed digital interface for audio/video appliances such as
digital television, digital video camcorders, storage peripherals & other PC portable devices.
ErP Ready
The motherboard is European Union’s Energy-related Products (ErP) ready, and ErP requires
products to meet certain energy efciency requirements in regards to energy consumptions.
This is in line with ASUS vision of creating environment-friendly and energy-efcient products
through product design and innovation to reduce carbon footprint of the product and thus
mitigate environmental impacts.
1-6Chapter 1: Product Introduction
Chapter 2
2.1 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.
ASUS SABERTOOTH 990FX2-1
2.2 Motherboard overview
2.2.1 Motherboard layout
Chapter 2
Refer to
2.2.8 Internal connectors
information about rear panel connectors and internal connectors.
2-2Chapter 2: Hardware information
and
2.3.10 Rear panel connection
for more
Layout contents
Connectors/Jumpers/SlotsPage
1. ATX power connectors (24-pin EATXPWR, 8-pin EATX12V)2-21
2. AM3+ CPU socket2-4
3. CPU and chassis fan connectors
(4-pin CPU_FAN, CPU_OPT FAN, CHA_FAN1~3, 3-pin
CHA_FAN4)
4. DDR3 DIMM slots2-5
5. MemOK! switch2-14
6. USB 3.0 connector (20-1 pin USB3_34)2-18
7. JMicron® Serial ATA 3.0 Gb/s connectors (7-pin SATA3G_E1/E2
[black])
8. AMD® Serial ATA 6.0 Gb/s connectors (7-pin SATA6G_1-6
[brown])
9. System panel connector (20-8 pin PANEL)2-23
10. Serial port connector (10-1 pin COM1)2-17
11. Clear RTC RAM (3-pin CLRTC)2-13
12. USB 2.0 connectors (10-1 pin USB1112, USB1314)2-18
13. Standby power LED (SB_PWR)2-15
14. IEEE 1394a port connector (10-1 pin IE1394_2)2-19
15. Front panel audio connector (10-1 pin AAFP)2-21
16. Digital audio connector (4-1 pin SPDIF_OUT)2-19
2-20
2-17
2-16
Chapter 2
ASUS SABERTOOTH 990FX2-3
2.2.2 Central Processing Unit (CPU)
+
The motherboard comes with an AM3+ socket designed for AMD® FX Series CPU up to 8-core,
also compatible with AMD® socket AM3 for AMD® Phenom™ II/Athlon™ II/ Sempron™ 100
Series Processors.
Chapter 2
Ensure that all power cables are unplugged before installing the CPU.
The AM3+ socket has a different pinout designe, ensure that you use a CPU designed for
the AM3+/AM3 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!
2-4Chapter 2: Hardware information
2.2.3 System memory
The motherboard comes with four Double Data Rate 3 (DDR3) Dual Inline Memory Modules
(DIMM) slots.
A DDR3 module is notched differently from a DDR or DDR2 module. DO NOT install a DDR
or DDR2 memory module to the DDR3 slot.
Recommended memory congurations
Chapter 2
ASUS SABERTOOTH 990FX2-5
Memory congurations
You may install 1GB, 2GB and 4GB unbuffered and non-ECC DDR3 DIMMs into the DIMM
sockets.
Chapter 2
• 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.
• Due to CPU behavior, DDR3 1800 MHz memory module will run at DDR3 1600 MHz
frequency as default.
• Always install DIMMs with the same CAS latency. For optimum compatibility, we
recommend that you obtain memory modules from the same vendor.
• Due to the memory address limitation on 32-bit Windows OS, when you install 4GB
or more memory on the motherboard, the actual usable memory for the OS can be
about 3GB or less. For effective use of memory, we recommend that you do any of the
following:
- Use a maximum of 3GB system memory if you are using a 32-bit Windows OS.
- Install a 64-bit Windows OS when you want to install 4GB or more on the
motherboard.
For more details, refer to the Microsoft® support site at
http://support.microsoft.com/kb/929605/en-us.
• This motherboard does not support DIMMs made up of 512Mb (64MB) chips or less
(Memory chip capacity counts in Megabit, 8 Megabit/Mb = 1 Megabyte/MB).
• 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. To operate at the vendor-marked
or at a higher frequency, refer to section
frequency adjustment.
• For system stability, use a more efcient memory cooling system to support a full