ASUS M4A785G HTPC RC, M4A785G HTPC User Manual
M4A785G HTPC
Series
Motherboard
E4849
First Edition V1
July 2009
Copyright © 2009 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
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.
ii
Contents
Contents ...................................................................................................... iii
Notices ......................................................................................................... vi
Safety information ..................................................................................... vii
About this guide ....................................................................................... viii
M4A785G HTPC Series specications summary ..................................... ix
Chapter 1 Product introduction
1.1 Welcome! ...................................................................................... 1-1
1.2 Package contents .........................................................................
1.3 Special features ............................................................................
1.3.1 Product highlights ...........................................................
1.3.2 Innovative ASUS features ...............................................
1.4 Before you proceed .....................................................................
1.5 Motherboard overview .................................................................
1.5.1 Placement direction ........................................................
1.5.2 Screw holes ....................................................................
1.5.3 Motherboard layout .........................................................
1.5.4 Layout contents ...............................................................
1.6 Central Processing Unit (CPU) ...................................................
1.6.1 Installing the CPU ...........................................................
1.6.2 Installing the heatsink and fan ........................................
1.7 System memory .........................................................................
1.7.1 Overview .......................................................................
1.7.2 Memory congurations ..................................................
1.7.3 Installing a DIMM ..........................................................
1.7.4 Removing a DIMM ........................................................
1.8 Expansion slots ..........................................................................
1.8.1 Installing an expansion card .........................................
1.8.2 Conguring an expansion card .....................................
1.8.3 PCI slot .........................................................................
1.8.4 PCI Express x1 slots .....................................................
1.8.5 PCI Express 2.0 x16 slot ...............................................
1.9 Jumpers ......................................................................................
1.10 Connectors .................................................................................
1.10.1 Rear panel connectors ..................................................
1.10.2 Internal connectors .......................................................
1-1
1-1
1-1
1-2
1-4
1-5
1-5
1-5
1-6
1-6
1-7
1-7
1-8
1-10
1-10
1-10
1-18
1-18
1-19
1-19
1-19
1-19
1-19
1-19
1-20
1-21
1-21
1-25
iii
Contents
1.11 Software support ........................................................................ 1-34
1.11.1 Installing an operating system ......................................
1.11.2 Support DVD information ..............................................
1.11.3 ASUS Home Theater Gate
Chapter 2 BIOS information
2.1 Managing and updating your BIOS ............................................ 2-1
2.1.1 ASUS Update utility ........................................................
2.1.2 ASUS EZ Flash 2 utility ...................................................
2.1.3 ASUS CrashFree BIOS 3 utility ......................................
2.2 BIOS setup program ....................................................................
2.2.1 BIOS menu screen ..........................................................
2.2.2 Menu bar .........................................................................
2.2.3 Navigation keys ...............................................................
2.2.4 Menu items .....................................................................
2.2.5 Submenu items ...............................................................
2.2.6 Conguration elds .........................................................
2.2.7 General help ...................................................................
2.2.8 Pop-up window ...............................................................
2.2.9 Scroll bar .........................................................................
2.3 Main menu ....................................................................................
2.3.1 System Time [xx:xx:xx] ...................................................
2.3.2 System Date [Day xx/xx/xxxx] .........................................
2.3.3 Language [English] .........................................................
2.3.4 Primary IDE Master/Slave ...............................................
2.3.5 SATA 1–5/ESATA ...........................................................
2.3.6 Storage Conguration .....................................................
2.3.7 System Information .........................................................
2.4 Ai Tweaker menu ..........................................................................
2.4.1 Ai Overclock Tuner [Auto] ...............................................
2.4.2 CPU Ratio [Auto] .............................................................
2.4.3 DRAM Frequency [Auto] .................................................
2.4.4 CPU/NB Frequency [Auto] ............................................
2.4.5 HT Link Frequency [Auto] .............................................
2.4.6 Memory Conguration ...................................................
2.4.7 DRAM Timing Conguration .........................................
............................................ 1-35
1-34
1-34
2-1
2-2
2-3
2-3
2-4
2-4
2-5
2-5
2-5
2-5
2-5
2-5
2-5
2-6
2-6
2-6
2-6
2-6
2-7
2-8
2-8
2-9
2-9
2-9
2-9
2-10
2-10
2-10
2-10
iv
Contents
2.4.8 CPU Voltage [Auto] ....................................................... 2-12
2.4.9 CPU/NB Voltage [Auto] .................................................
2.4.10 DRAM Voltage [Auto] ....................................................
2.4.11 NB Voltage [Auto] ..........................................................
2.4.12 HT/SB Voltage [Auto] ....................................................
2.4.13 CPU Spread Spectrum [Auto] .......................................
2.4.14 PCIE Spread Spectrum [Auto] ......................................
2.5 Advanced menu .........................................................................
2.5.1 CPU Conguration ........................................................
2.5.2 Chipset ..........................................................................
2.5.3 Onboard Devices Conguration ....................................
2.5.4 USB Conguration ........................................................
2.5.5 PCIPnP .........................................................................
2.6 Power menu ................................................................................
2.6.1 Suspend Mode [Auto] ...................................................
2.6.2 ACPI 2.0 Support [Disabled] .........................................
2.6.3 ACPI APIC support [Enabled] .......................................
2.6.4 Chassis LED [On] .........................................................
2.6.5 EuP Ready [Disabled] ...................................................
2.6.6 APM Conguration ........................................................
2.6.7 Hardware Monitor .........................................................
2.7 Boot menu ..................................................................................
2.7.1 Boot Device Priority ......................................................
2.7.2 Boot Settings Conguration ..........................................
2.7.3 Security .........................................................................
2.8 Tools menu .................................................................................
2.8.1 ASUS EZ Flash 2 ..........................................................
2.8.2 Express Gate [Auto] ......................................................
2.8.3 AI NET 2
2.9 Exit menu ....................................................................................
........................................................................ 2-21
2-12
2-12
2-12
2-12
2-12
2-12
2-13
2-13
2-14
2-15
2-15
2-16
2-16
2-17
2-17
2-17
2-17
2-17
2-17
2-18
2-19
2-19
2-19
2-20
2-21
2-21
2-21
2-22
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://green.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.
• The optical S/PDIF is an optional component (may or may not be included in your
motherboard) and is dened as a CLASS 1 LASER PRODUCT.
INVISIBLE LASER RADIATION, AVOID EXPOSURE TO BEAM.
• Never dispose of the battery in re. It could explode and release harmful substances into
the environment.
• Never dispose of the battery with your regular household waste. Take it to a hazardous
material collection point.
• Never replace the battery with an incorrect battery type.
• RISK OF EXPLOSION IF BATTERY IS REPLACED BY AN INCORRECT TYPE.
• DISPOSE OF USED BATTERIES ACCORDING TO THE ABOVE BATTERY-RELATED
INSTRUCTIONS.
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.
This motherboard should only be used in environments with ambient temperatures between
5°C (41°F) and 40°C (104°F).
• 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: BIOS setup
This chapter tells how to change system settings through the BIOS Setup menus.
Detailed descriptions of the BIOS parameters are also provided.
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 complete a task.
CAUTION: Information to prevent damage to the components
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.
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.
Typography
Bold text Indicates a menu or an item to select.
Italics
Used to emphasize a word or a phrase.
<Key> Keys enclosed in the less-than and greater-than sign means
that you must press the enclosed key.
Example: <Enter> means that you must press the Enter or
Return key.
<Key1>+<Key2>+<Key3> If you must press two or more keys simultaneously, the key
names are linked with a plus sign (+).
Example: <Ctrl>+<Alt>+<D>
viii
M4A785G HTPC Series specications summary
CPU AMD® AM3/AM2+/AM2 Phenom™ II / Athlon™ II /
Chipset AMD® 785G / SB710
System bus Up to 5200 MT/s; HyperTransport™ 3.0 interface for
Memory Dual-channel memory architecture
Graphics Integrated ATI Radeon™ HD 4200 GPU
Expansion Slots 1 x PCIe 2.0 x16 slot
Phenom™ / Athlon™ / Sempron™ Processors
AMD® 45nm CPU support
AMD Cool’n’Quiet™ Technology
AM3 / AM2+ CPU
2000 / 1600 MT/s for AM2 CPU
- 4 x 240-pin DIMM sockets support unbufferred
ECC / non-ECC DDR2 1200(O.C)* / 1066* / 800 /
667 MHz memory modules
- Supports up to 16GB system memory
* Due to AMD® CPU limitation, DDR2 1200/1066 are
supported by AM3 / AM2+ CPUs for one DIMM per channel
only. Refer to www.asus.com or this user manual for the
Memory QVL (Qualied Vendors Lists).
** 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.
- Supports HDMI™ Technology with max. resolution up
to 1920 x 1200 (1080P)
- Supports Dual-link DVI with max. resolution up to
2560 x 1600 @ 60Hz
- Supports D-Sub with max. resolution up to
2560 x 1440 @ 75Hz for 16:9 format
- Hybrid CrossFireX™ support
- Dual independent displays support with HDMI / DVI
and D-Sub)
- Supports Microsoft® DirectX 10.1, OpenGL 2.0,
Pixel Shader 4.0
- Hardware Decode Acceleration for H.264, VC-1, and
MPEG-2
- Maximum shared memory of 512MB
2 x PCIe x1 slots
1 x PCI 2.2 slot
(continued on the next page)
ix
M4A785G HTPC Series specications summary
Storage SB710 Chipset:
- 1 x Ultra DMA 133/100/66 for up to 2 PATA devices
- 5 x SATA 3.0 Gb/s ports with RAID 0, 1 and 10 support
- 1 x External SATA 3.0 Gb/s port
* Due to Window® XP/Vista™ limitation, the RAID array with
the total capacity over 2TB cannot be set as a boot disk. A
RAID array over 2TB can only be set as a data disk only.
LAN Realtek® 8112L Gigabit LAN controller featuring AI NET 2
High Denition Audio Absolute Pitch Hi-Fi featuring ENVY HD
- 9.1-channel High Denition Audio
- DTS Surround Sensation UltraPC
(supports Windows® Vista™ and Windows® 7 only)
- Lossless 192khz/24-bit BD audio
- Supports Jack-Detection and Multi-Streaming
- 2-channel gold-plated RCA output at back I/O
- Optical S/PDIF Out port at back I/O
IEEE 1394a JMicron® JMB381 controller supports 2 x IEEE 1394a ports
USB 10 x USB 2.0 /1.1 ports (6 ports at midboard; 4 ports at
back panel)
AI HTPC Unique
Features
ASUS HTPC Features:
- ASUS Absolute Pitch Hi-Fi
- ASUS Home Theater Gate
- ASUS Tranquil Mode (AM3/AM2+ CPUs only)
- DTS Surround Sensation UltraPC (supports Windows
®
Vista™ and Window® 7 only)
ASUS Express Gate
ASUS Quiet Thermal Solution
- ASUS Fanless Design: Soundwave Heat-sink
ASUS EZ DIY
- ASUS Q-Connector
- ASUS CrashFree BIOS 3
- ASUS EZ Flash 2
Other Features ASUS MyLogo 2™
(continued on the next page)
x
M4A785G HTPC Series specications summary
ASUS Exclusive
Overclocking Features
Rear panel I/O ports 1 x S/PDIF Out port (Optical)
Internal I/O connectors 3 x USB connectors support 6 USB ports
Precision Tweaker:
- vCore: Adjustable CPU voltage at 0.0125V increment
SFS (Stepless Frequency Selection):
- FSB tuning from 200MHz up to 600MHz at 1MHz
increment
- GPU tuning from 500MHz up to 1500MHz
- PCIe frequency tuning from 100MHz up to 150MHz at
1MHz increment
Overclocking protection:
- ASUS C.P.R. (CPU Parameter Recall)
2-channel RCA audio output ports
1 x HDMI Out port
1 x D-Sub Out port
1 x DVI Out port
1 x IEEE 1394a port
1 x LAN (RJ-45) port
4 x USB 2.0/1.1 ports
1 x External SATA port
10-channel audio I/O ports
1 x IDE connector
5 x SATA connectors
1 x CPU Fan connector
2 x Chassis Fan connector
1 x Power Fan connector
1 x IEEE1394a connector
1 x Front panel audio connector
1 x S/PDIF Out Header
1 x CD audio in
1 x 24-pin ATX Power connector
1 x 4-pin ATX 12V Power connector
1 x 4-pin ATX Audio Power connector
1 x System Panel (Q-Connector)
(continued on the next page)
xi
M4A785G HTPC Series specications summary
BIOS features 16 Mb Flash ROM, AMI BIOS, PnP, DMI 2.0, WfM2.0,
Support DVD contents Drivers
Form factor uATX form factor: 9.6 in x 9.6 in (24.4 cm x 24.4 cm)
*Specications are subject to change without notice.
SM BIOS 2.5, ACPI 2.0
ASUS Home Theater Gate
ASUS Express Gate
ASUS PC Probe II
ASUS Update
Anti-Virus Utility (OEM version)
xii
Chapter 1
Product introduction
1.1 Welcome!
Thank you for buying an ASUS® M4A785G HTPC Series 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.
Motherboard ASUS M4A785G HTPC Series motherboard
Cables 1 x Ultra DMA 133/100/66 cable
2 x Serial ATA signal cables
Accessories 1 x I/O shield
1 x 2 in 1 Q-connector (USB and system panel;
Retail version only)
1 x ASUS Home Theater Gate Remote Controller set
(RC Edition only)
Application DVD ASUS motherboard support DVD
Documentations User manual
If any of the above items is damaged or missing, contact your retailer.
1.3 Special features
1.3.1 Product highlights
AMD® Phenom™ II / Athlon™ II / Sempron™ 100 Series
Chapter 1: Product introduction 1-1
processors (AM3 CPU)
This motherboard supports AMD® AM3 multi-core processors with
unique L3 cache and delivers better overclocking capabilities with less
power consumption. It features dual-channel DDR2 1200(O.C.)/1066
memory support and accelerates data transfer rate up to 5200MT/s via
HyperTransort™ 3.0 based system bus. This motherboard also supports
AMD® CPUs in the new 45nm manufacturing process.
AMD® Phenom™ X4 / Phenom™ X3 / Athlon™ X2 / Athlon™ /
Sempron™ processors (socket AM2+ / AM2)
The motherboard supports AMD® Socket AM2+ multi-core processors.
It features dual-channel DDR2 1200(O.C.)/1066 memory support, data
transfer rate up to 5200MT/s via HyperTransport™ 3.0 based system bus
and AMD® Cool ‘n’ Quiet!™ Technology.
AMD® 785G chipset
The AMD® 785G Northbridge is the latest AMD chipset designed for both
HT1.0 and 5200MT/s HyperTransport™ 3.0 (HT 3.0) interface speed and
external graphics in PCI Express 2.0 standard. It features the integrated
ATI Radeon™ HD 4200 GPU and fully Directx 10.1 compliant.
Dual channel DDR2 1200(O.C.)/1066 support
This motherboard supports DDR2 1200(O.C.)/1066, which provides faster
data transfer rate and more bandwidth to increase memory data transfer
rate and computing efciency. This enhances system performance in 3D
graphics and other memory demanding applications.
Due to AM3/AM2+ CPU limitation, only one DDR2 1200(O.C.)/1066 is supported per
channel. When four DDR2 1200(O.C.)/1066 DIMMs are installed, all DIMMs run at
800MHz frequency by default for system stability.
AMD® Hybrid CrossFireX Technology
Hybrid CrossFireX Technology is a unique multi-GPU technology
combining the onboard GPU and the discrete graphics card together to
enhance 3D graphics performance.
Visit www.amd.com for the Hybrid CrossreX selected GPUs.
1.3.2 Innovative ASUS features
ASUS HTPC Features
Absolute Pitch Hi-Fi
You can easily experience home theater enjoyment on your computer with
the revolutionary ASUS Absolute Pitch Hi-Fi technology, which features
ENVY HD, Absolute Pitch BD192/24, and DTS Surround Sensation
UltraPC. ENVY HD feaures prodigious 9.1 high denition audio and
ne-textured graphic user interface that simply brings the professional
surround acoustic level to your computer. Absolute Pitch BD192/24
delivers 192khz/24bit Hi-Fi BD lossless, extreme delity sound to bring
true BD audio technology to your home theater PC. DTS Surround
Sensation UltraPC provides proprietary DTS algorithms to deliver virtual
5.1 surround through just 2 speakers.
1-2 ASUS M4A785G HTPC Series
Independent Audio Power Connector
Power is the key determinant in audio quality, thus, professional AV (Audio
Visual) equipment usually separate power supply for different channels
or analog/digital signals to ensure high sound quality. The ASUS HTPC
series is the rst motherboard series to be equipped with the revolutionary
ASUS Absolute Pitch Hi-Fi technology, which utilizes audio components
with an independent power connector. This effectively reduces electronic
noise to ensure purer sound quality.
Gold-plated RCA Connector
The gold-plated RCA stereo audio connectors are compatible with
ampliers without requiring additional connectors–making it simple to link
PCs to home theater equipment. The gold-plated cover ensures maximum
conductivity and durability of the connector.
For better sound quality, connect a power plug to the 4-pin audio power connector. Refer
to page 1-31 for details.
ASUS Tranquil Mode
The revolutionary ASUS Tranquil Mode effectively reduces fan speeds,
which lower the CPU power usage while increasing energy efciency. With
the reduction in fan speeds, the noise also decreases, thus providing you
with the perfect environment to enjoy watching movies or playing music.
ASUS Tranquil Mode is supported by AM3/AM2+ CPU only.
ASUS Home Theater Gate
The ASUS Home Theater Gate, specially designed for the HTPC series,
allows you to easily and quickly launch media applications to enjoy your
music and movies.
For RC Edition: Use the bundled remote controller to launch the ASUS
Home Theater Gate and start media applications.
ASUS Unique Features
ASUS Express Gate
Express Gate is an ASUS exclusive OS, which lets you instantly access
the Internet and key applications before entering Windows®.
The actual boot time depends on the system conguration.
Chapter 1: Product introduction 1-3
1.4 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, switch off the ATX power supply and
detach its power cord. Failure to do so may cause severe damage to the motherboard,
peripherals, or components.
Onboard LED
The motherboard comes with a standby power LED that lights up to indicate that the system
is ON, in sleep mode, or in soft-off mode. This is a reminder that you should shut down
the system and unplug the power cable before removing or plugging in any motherboard
component. The illustration below shows the location of the onboard LED.
1-4 ASUS M4A785G HTPC Series
1.5 Motherboard overview
1.5.1 Placement direction
When installing the motherboard, ensure that you place it into the chassis in the correct
orientation. The edge with external ports goes to the rear part of the chassis as indicated in
the image below.
1.5.2 Screw holes
Place eight screws into the holes indicated by circles to secure the motherboard to the
chassis.
Do not overtighten the screws! Doing so can damage the motherboard.
Place this side towards
the rear of the chassis.
Chapter 1: Product introduction 1-5
1.5.3 Motherboard layout
1.5.4 Layout contents
Connectors/Jumpers/Slots Page
1. ATX power connectors (24-pin EATXPWR, 4-pin ATX12V) 1-26
2. CPU, Chassis and Power Fan connectors (4-pin CPU_FAN, 4-pin CHA_FAN1,
3-pin CHA_FAN2, 3-pin PWR_FAN)
3. CPU socket AM2+/AM2
4. DDR2 DIMM slots
5. Serial ATA connectors (7-pin SATA1-5)
6. IDE connector (40-1 pin PRI_IDE)
7. Onboard LED (SB_PWR)
8. Clear RTC RAM (CLRTC)
9. System panel connector (10-1 pin PANEL)
10. USB connectors (10-1 pin USB56, USB78, USB910)
11. IEEE 1394a port connector (10-1 pin IE1394_2)
12. Audio power connector (4-pin AUDIO_PWR)
13. Optical drive audio in connector (4-pin CD)
14. Front panel audio connector (10-1 pin AAFP)
15. Digital audio connector (4-1 pin SPDIF_OUT)
1-6 ASUS M4A785G HTPC Series
1-25
1-7
1-10
1-28
1-27
1-4
1-20
1-29
1-30
1-32
1-31
1-30
1-32
1-31
1.6 Central Processing Unit (CPU)
The motherboard comes with a CPU socket designed for AMD® AM3/AM2+/AM2 Phenom™ II /
Athlon™ II / Phenom™ / Athlon™ / Sempron™ processors.
The CPU socket is not compatible with AMD® Opteron™ processors. Do not install an
Opteron™ processor on this motherboard.
1.6.1 Installing the CPU
To install a CPU:
1. Locate the CPU socket on the motherboard.
2. Press the lever sideways to unlock
the socket, then lift it up to a
90°–100° angle.
Socket lever
Ensure that the socket lever is lifted up to 90°–100° angle, otherwise the CPU will not t in
completely.
3. Position the CPU above the socket such that the CPU
corner with the gold triangle matches the socket corner
with a small triangle.
4. Carefully insert the CPU into the socket until it ts in place.
The CPU ts only in one correct
orientation. DO NOT force the CPU into
the socket to prevent bending the pins
and damaging the CPU!
Chapter 1: Product introduction 1-7
Small triangle
Gold triangle
5. When the CPU is in place, push down the socket
lever to secure the CPU. The lever clicks on the side
tab to indicate that it is locked.
6. Install a CPU heatsink and fan following the
instructions that came with the heatsink package.
You can also refer to section 1.6.2 Installing the
heatsink and fan for instructions.
7. Connect the CPU fan cable to the CPU_FAN
connector on the motherboard.
Do not forget to connect the CPU
fan connector! Hardware monitoring
errors can occur if you fail to plug this
connector.
1.6.2 Installing the heatsink and fan
Ensure that you use only AMD-certied heatsink and fan assembly.
To install the CPU heatsink and fan:
1. Place the heatsink on top of the installed CPU, making sure that the heatsink ts
properly on the retention module base.
• The retention module base is already installed on the motherboard upon purchase.
• You do not have to remove the retention module base when installing the CPU or
installing other motherboard components.
• If you purchased a separate CPU heatsink and fan assembly, ensure that a Thermal
Interface Material is properly applied to the CPU heatsink or CPU before you install the
heatsink and fan assembly.
CPU Fan
CPU Heatsink
Retention bracket
Retention Module Base
Retention bracket lock
1-8 ASUS M4A785G HTPC Series
Your boxed CPU heatsink and fan assembly should come with installation instructions for
1
3
4
5
2
the CPU, heatsink, and the retention mechanism. If the instructions in this section do not
match the CPU documentation, follow the latter.
2. Attach one end of the retention bracket to the retention module base.
3. Align the other end of the retention bracket to the retention module base. A clicking
sound denotes that the retention bracket is in place.
Ensure that the fan and heatsink assembly perfectly ts the retention mechanism module
base, otherwise you cannot snap the retention bracket in place.
4. Push down the retention bracket lock on the retention mechanism to secure the
heatsink and fan to the module base.
5. When the fan and heatsink assembly is in place, connect the CPU fan cable to the
connector on the motherboard labeled CPU_FAN.
Do not forget to connect the CPU fan connector! Hardware monitoring errors can occur if
you fail to plug this connector.
Chapter 1: Product introduction 1-9
1.7 System memory
1.7.1 Overview
The motherboard comes with four Double Data Rate 2 (DDR2) Dual Inline Memory Modules
(DIMM) sockets. A DDR2 module has the same physical dimensions as a DDR DIMM but
has a 240-pin footprint compared to the 184-pin DDR DIMM. DDR2 DIMMs are notched
differently to prevent installation on a DDR DIMM socket. The gure illustrates the location of
the DDR2 DIMM sockets:
Channel Sockets
Channel A DIMM_A1 and DIMM_A2
Channel B DIMM_B1 and DIMM_B2
1.7.2 Memory congurations
You may install 512MB, 1GB, 2GB and 4GB unbuffered ECC/non-ECC DDR2 DIMMs into the
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 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 install a 64-bit
Windows OS when having 4GB or more memory installed on the motherboard.
• This motherboard does not support DIMMs made up of 256 Mb chips or less. (Memory
chip capacity counts in Megabit, 8 Megabit/Mb=1 Megabyte/MB.)
• Due to AM3/AM2+ CPU limitation, only one DDR2 1200(O.C.)/1066 DIMM is supported
per channel. When four DDR2 1200(O.C.)/1066 DIMMs are installed, all DIMMs run at
800Mhz frequency by default for system stability.
• The default memory operation frequency is dependent on its SPD. 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) or overclocking condition.
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