Asus M3A78-CM - Motherboard - Micro ATX User manual

Motherboard
M3A78-CM

ii
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, modied or altered, unless
such repair, modication of alteration is authorized in writing by ASUS; or (2) the serial number of the
product is defaced or missing.
ASUS PROVIDES THIS MANUAL “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OR CONDITIONS OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL ASUS, ITS
DIRECTORS, OFFICERS, EMPLOYEES OR AGENTS BE LIABLE FOR ANY INDIRECT, SPECIAL,
INCIDENTAL, OR CONSEQUENTIAL DAMAGES (INCLUDING DAMAGES FOR LOSS OF PROFITS,
LOSS OF BUSINESS, LOSS OF USE OR DATA, INTERRUPTION OF BUSINESS AND THE LIKE),
EVEN IF ASUS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES ARISING FROM ANY
DEFECT OR ERROR IN THIS MANUAL OR PRODUCT.
SPECIFICATIONS AND INFORMATION CONTAINED IN THIS MANUAL ARE FURNISHED FOR
INFORMATIONAL USE ONLY, AND ARE SUBJECT TO CHANGE AT ANY TIME WITHOUT NOTICE,
AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY ASUS. ASUS ASSUMES NO
RESPONSIBILITY OR LIABILITY FOR ANY ERRORS OR INACCURACIES THAT MAY APPEAR IN THIS
MANUAL, INCLUDING THE PRODUCTS AND SOFTWARE DESCRIBED IN IT.
Products and corporate names appearing in this manual may or may not be registered trademarks or
copyrights of their respective companies, and are used only for identication or explanation and to the
owners’ benet, without intent to infringe.
E4420
Fourth Edition V4
January 2009

iii
Contents
Notices......................................................................................................... vi
Safety information ..................................................................................... vii
About this guide ........................................................................................ vii
M3A78-CM specications summary ......................................................... ix
Chapter 1: Product introduction
1.1 Welcome! ...................................................................................... 1-1
1.2 Package contents......................................................................... 1-1
1.3 Special features............................................................................ 1-1
1.3.1 Product highlights ........................................................... 1-1
1.3.2 Innovative ASUS features ............................................... 1-3
1.4 Before you proceed ..................................................................... 1-5
Onboard LED ................................................................................. 1-5
1.5 Motherboard overview................................................................. 1-6
1.5.1 Placement direction ........................................................ 1-6
1.5.2 Screw holes .................................................................... 1-6
1.5.3 Motherboard layout ......................................................... 1-7
1.5.4 Layout contents............................................................... 1-7
1.6 Central Processing Unit (CPU) ................................................... 1-8
1.6.1 Installing the CPU ........................................................... 1-8
1.6.2 Installing the heatsink and fan ...................................... 1-10
1.7 System memory ......................................................................... 1-11
1.7.1 Overview ........................................................................1-11
1.7.2 Memory congurations.................................................. 1-12
1.7.3 Installing a DIMM .......................................................... 1-15
1.6.4 Removing a DIMM ........................................................ 1-15
1.8 Expansion slots.......................................................................... 1-16
1.8.1 Installing an expansion card ......................................... 1-16
1.8.2 Conguring an expansion card ..................................... 1-16
1.8.4 PCI slots........................................................................ 1-16
1.8.5 PCI Express x1 slot....................................................... 1-16
1.8.6 PCI Express x16 slot..................................................... 1-16
1.9 Jumpers ...................................................................................... 1-17
1.10 Connectors ................................................................................. 1-18
1.10.1 Rear panel connectors.................................................. 1-18
1.10.2 Internal connectors .........................................................1-20

iv
Contents
1.11 Software support........................................................................ 1-27
1.11.1 Installing an operating system ...................................... 1-27
1.11.2 Support DVD information .............................................. 1-27
Chapter 2: BIOS information
2.1 Managing and updating your BIOS ............................................ 2-1
2.1.1 Creating a bootable oppy disk....................................... 2-1
2.1.2 ASUS Update utility ........................................................ 2-2
2.1.3 ASUS EZ Flash 2 utility................................................... 2-3
2.1.4 AFUDOS utility................................................................ 2-4
2.1.5 ASUS CrashFree BIOS 3 utility ...................................... 2-5
2.2 BIOS setup program .................................................................... 2-6
2.2.1 BIOS menu screen.......................................................... 2-7
2.2.2 Menu bar......................................................................... 2-7
2.2.3 Navigation keys............................................................... 2-8
2.2.4 Menu items ..................................................................... 2-8
2.2.5 Submenu items ............................................................... 2-8
2.2.6 Conguration elds ......................................................... 2-8
2.2.7 General help ................................................................... 2-8
2.2.8 Pop-up window ............................................................... 2-8
2.2.9 Scroll bar......................................................................... 2-8
2.3 Main menu .................................................................................... 2-9
2.3.1 System Time .................................................................. 2-9
2.3.2 System Date .................................................................. 2-9
2.3.3 Legacy Diskette A ........................................................... 2-9
2.3.4 Primary IDE Master/Slave and SATA 1~6....................... 2-9
2.3.5 SATA Conguration ....................................................... 2-10
2.3.6 System Information ........................................................2-11
2.4 Advanced menu ......................................................................... 2-11
2.4.1 JumperFree Conguration .............................................2-11
2.4.2 CPU Conguration ........................................................ 2-12
2.4.3 Chipset.......................................................................... 2-13
2.4.4 Onboard Devices Conguration.................................... 2-15
2.4.5 PCI PnP ........................................................................ 2-15
2.4.6 USB Conguration ........................................................ 2-16
2.5 Power menu................................................................................ 2-17

v
Contents
2.5.1 Suspend Mode ............................................................. 2-17
2.5.2 ACPI Support ................................................................ 2-17
2.5.3 ACPI APIC Support ...................................................... 2-17
2.5.4 APM Conguration........................................................ 2-17
2.5.5 HW Monitor Conguration............................................. 2-18
2.6 Boot menu .................................................................................. 2-19
2.6.1 Boot Device Priority ...................................................... 2-19
2.6.2 Boot Settings Conguration .......................................... 2-19
2.6.3 Security ......................................................................... 2-20
2.7 Tools menu ................................................................................. 2-22
2.7.1 ASUS EZ Flash 2.......................................................... 2-22
2.7.2 Express Gate [Enabled] ................................................ 2-22
2.8 Exit menu.................................................................................... 2-23

vi
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 modications 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.
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.

vii
Safety information
Electrical safety
• To prevent electrical shock hazard, disconnect the power cable from the electrical outlet
before relocating the system.
• When adding or removing devices to or from the system, ensure that the power cables
for the devices are unplugged before the signal cables are connected. If possible,
disconnect all power cables from the existing system before you add a device.
• Before connecting or removing signal cables from the motherboard, ensure that all
power cables are unplugged.
• Seek professional assistance before using an adapter or extension cord. These devices
could interrupt the grounding circuit.
• Ensure that your power supply is set to the correct voltage in your area. If you are not
sure about the voltage of the electrical outlet you are using, contact your local power
company.
• If the power supply is broken, do not try to x it by yourself. Contact a qualied service
technician or your retailer.
Operation safety
• Before installing the motherboard and adding devices on it, carefully read all the manuals
that came with the package.
• Before using the product, ensure that all cables are correctly connected and the power
cables are not damaged. If you detect any damage, contact your dealer immediately.
• To avoid short circuits, keep paper clips, screws, and staples away from connectors,
slots, sockets and circuitry.
• Avoid dust, humidity, and temperature extremes. Do not place the product in any area
where it may become wet.
• Place the product on a stable surface.
• If you encounter technical problems with the product, contact a qualied service
technician or your retailer.
About this guide
This user guide contains the information you need when installing and conguring the
motherboard.
How this guide is organized
This guide contains the following parts:
• Chapter 1: Product introduction
This chapter describes the features of the motherboard and the new technology it
supports.
• Chapter 2: BIOS information
This chapter tells how to change system settings through the BIOS Setup menus.
Detailed descriptions of the BIOS parameters are also provided.

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 complete a task.
CAUTION: Information to prevent damage to the components
when trying to complete a task.
NOTE: Tips and additional information to help you complete a
task.
IMPORTANT: Instructions that you MUST follow to 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>
Command Means that you must type the command exactly as shown,
then supply the required item or value enclosed in
brackets.
Example: At the DOS prompt, type the command line:
afudos /i[lename]
afudos /iM3A78CM.ROM

ix
M3A78-CM specications summary
(continued on the next page)
CPU AMD® Socket AM2+ / AM2 for AMD Phenom™FX / Phenom/
Athlon™ / Sempron™ processor
AMD64 architecture enables simultaneous 32-bit
and 64-bit computing
Supports up to 140W CPU
AMD Live!™ Ready
AMD Cool ‘n’ Quiet™ Technology
Chipset AMD 780V / SB700
System bus Up to 5200 MT/s HyperTransport™ 3.0 interface for AM2+ CPU
2000 / 1600 MT/s for AM2 CPU
Memory Dual-channel memory architecture
4 x 240-pin DIMM slots support unbuffered ECC and non-ECC
DDR2 1066/800/667/533MHz
Supports up to 8GB system memory
* Due to AM2+ CPU limitation, only one DDR2 1066 DIMM is
supported per channel. When four DDR2 1066 DIMMs are
installed, all DIMMs run at 800MHz frequency by default for
system stability.
** Refer to www.asus.com or user manual for Memory QVL
(Qualied Vendors List)
*** 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.
Expansion slots 1 x PCI Express™ x16 slot
1 x PCI Express™ x1 slot
2 x PCI 2.2 slots
Support PCI Express™ 2.0 / 1.0 Architecture
Storage / RAID 1 x UltraDMA 133/100 connector
6 x Serial ATA 3Gb/s connectors support RAID 0, RAID 1,
RAID 0+1 conguration
Audio High Denition Audio 8-channel CODEC
Supports Jack-Detect, Multistreaming Technologies, and
S/PDIF Out interface
USB Supports up to 12 USB 2.0/1.1 ports (6 ports at mid-board,
6 ports at the back panel)
LAN PCIe Gigabit LAN
Back panel I/O
ports
1 x PS/2 Keyboard port
1 x DVI port
1 x DisplayPort port
1 x VGA port
1 x RJ45 port
6 x USB 2.0/1.1 ports
8-channel Audio I/O ports

x
M3A78-CM specications summary
Internal I/O
connectors
3 x USB 2.0 connectors support additional 6 USB 2.0/1.1 ports
1 x Floppy disk drive connector
1 x IDE connector
1 x COM connector
6 x SATA connectors
High denition front panel audio connector
1 x system panel connector
1 x CD audio-in connector
1 x S/PDIF output connector
1 x TPM Header
1 x Printer port
Power/CPU/Chassis fan connectors
24-pin EATX power connector
4-pin ATX 12V power connector
Graphics Integrated ATI RV610-based Direct x10.0 graphics
Supports maximum shared memory up to 256MB
Supports DisplayPort with max. resolution up to 2560 x 1600
@60Hz
Supports DVI-D with HDCP compliant with max. resolution up to
2560 x 1600 @60Hz dual-link
Supports RGB with max. resolution up to 2048 x 1536 @85Hz
Dual VGA output supports: RGB & DVI, DVI & DP, and RGB & DP
* To playback the HD-DVD and Blu ray Disc, we recommend
system conguration above Graphic shared memory 256MB/
Dual-Core CPU minimum/Minimum 1GB memory of Dual-
channel DDR2 667 or Single-channel DDR2 800.
ASUS special
features
ASUS Q-Fan
ASUS CrashFree BIOS3
ASUS EZ Flash2
ASUS MyLogo2
AI NET2
Express Gate
ASUS Overclocking
features
SFS (Stepless Frequency Selection) from 200MHz to 400MHz
at 1MHz increment
Adjustable DRAM voltage
ASUS CPR (CPU Parameter Recall)
BIOS 8Mb Flash ROM, AMI BIOS, PnP, DMI2.0, WfM2.0, ACPI2.0,
SMBIOS 2.5
Accessories User manual
1 x Serial ATA signal cable
1 x Serial ATA power cable
1 x UltraDMA 133/100/66 cable
1 x FDD cable
1 x I/O shield
Form Factor uATX Form factor: 9.6’’ x 9.6’’ (24.4cm x 24.4cm)
Support DVD Drivers
ASUS PC Probe II
ASUS LiveUpdate Utilitys
Anti-Virus software (OEM version)
*Specications are subject to change without notice.

1.2 Package contents
Check your motherboard package for the following items.
Motherboard ASUS M3A78-CM motherboard
Cables 1 x Serial ATA signal cable
1 x Serial ATA power cable
1 x Ultra DMA 133/100 cable
1 x FDD cable
Accessories 1 x I/O shield
Application DVD ASUS motherboard support DVD
Documentations User manual
If any of the above items is damaged or missing, contact your retailer.
Chapter 1
Product introduction
AMD®Socket AM2+ Phenom™ FX / Phenom™ / Athlon™
CPU support
This motherboard supports AMD® Socket AM2+ multi-core processors
with unique L3 cache and delivers better overclocking capabilities
with less power consumption. It features dual-channel DDR2 1066
memory support and accelerates data transfer rate up to 5200MT/s via
HyperTransport™ 3.0 based system bus.
1.3 Special features
1.3.1 Product highlights
1.1 Welcome!
Thank you for buying an ASUS®M3A78-CM 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.
Chapter 1: Product introduction 1-1

AMD®Socket AM2 Athlon™ / Sempron™ CPU support
The motherboard supports AMD® Socket AM2 Athlon™ processors. It
features 2000 / 1600 MT/s HyperTransport™-based system bus, dual-
channel un-buffered DDR2 800 memory support and AMD™ Cool ‘n’
Quiet™ Technology.
MT/s
5200
HyperTransport™ 3.0 support
HyperTransport™ 3.0 technology provides 2.6 times more bandwidth
than HT1.0 that radically improves system efciency for a smoother,
faster computing environment.
64-bit CPU support
64-bit computing, the next generation technology to replace the current
32-bit architecture, delivers advanced system performance, faster
memory access, and increased productivity. This motherboard provides
excellent compatibility and exibility by supporting either 64-bit or 32-bit
architecture.
Dual-core CPU
Enjoy the extraordinary CPU power from the latest dual-core CPU. The
advanced processing technology contains two physical CPU cores with
individually dedicated L2 cache to satisfy the rising demand for more
powerful processing capability.
Gigabit LAN solution
The onboard LAN controller is a highly integrated Gb LAN controller.
It is enhanced with an ACPI management function to provide efcient
power management for advanced operating systems.
AMD Cool ‘n’ Quiet Technology
The motherboard supports the AMD Cool ‘n’ Quiet Technology, which
monitors system operation and automatically adjusts CPU voltage and
frequency for a cool and quiet operating environment.
Dual channel DDR2 1066 support
This motherboard supports DDR2 1066, which provides faster data
transfer rate and more bandwidth to increase memory data transfer
rate and computing efciency. This enhances system performance in
3D graphics and other memory demanding applications.
• DDR2 1066 is supported by AM2+ CPU only. Refer to the ASUS website at
www.asus.com for the supported CPU models.
• Due to AM2+ CPU limitation, only one DDR2 1066 DIMM is supported per channel.
When four DDR2 1066 DIMMs are installed, all DIMMs run at 800MHz frequency by
default for system stability.
PCI Express 2.0 support
This motherboard supports the latest PCIe 2.0 devices for double
speed and bandwidth which enhances system performance.
1-2 ASUS M3A78-CM

AMD 780V
The AMD 780V 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 RV610-based graphics and fully DirectX 10.0 compliant.
DVI Interface
DVI (Digital Visual Interface) provides high visual quality of digital
display devices such as LCD monitors. The interface of this
motherboard supports dual VGA output both DVI and RGB and HDCP
compliant allowing playback of HD DVD and Blu-ray Disc.
To ensure high visual quality, install Windows Media Player 11 or later versions when
you connect a display monitor to the DisplayPort, VGA, or DVI port, or when you connect
two display monitors to any two of these three ports.
DisplayPort
This motherboard introduces the new digital display interface standard
- DisplayPort. This new design features a small and user-friendly
connector. It delivers higher performance of resolution, refresh rate,
and color depth and improves digital display connectivity.
Serial ATA 3Gb/s technology
The motherboard supports next-generation SATA hard drives based on
the new SATA 3Gb/s storage specication. The onboard Southbridge
chipset allows RAID 0, RAID 1, RAID 0+1, and JBOD congurations for
Serial ATA drives.
8-channel High Denition Audio
The onboard 8-channel VT1708B/S High Denition Audio CODEC
enables high-quality audio that automatically detects peripherals
plugged into the audio I/O jacks. VT1708B/S also supports the
Windows®Vista Premium OS.
USB 2.0 technology
USB 2.0 is the latest connectivity standard for next generation
components and peripherals. Backwards compatible with current USB
1.1 peripherals, USB 2.0 delivers transfer speeds up to 40 times faster
at 480Mb/s, for easy connectivity and ultra-fast data transfers.
1.3.2 Innovative ASUS features
ASUS MyLogo2™
Turn your favorite photos into 256-color boot logos to personalize your
system.
ASUS CrashFree BIOS 3
ASUS CrashFree BIOS 3 is an auto-recovery tool that allows you to
restore a corrupted BIOS le using the bundled support DVD, oppy
disk, or USB disk that contains the BIOS le.
Chapter 1: Product introduction 1-3

ASUS EZ Flash 2
ASUS EZ Flash 2 is a utility that allows you to update the BIOS without
using a bootable oppy disk or a DOS-based utility.
ASUS Q-Fan
ASUS Q-Fan technology intelligently adjusts CPU fan speeds
according to system loading to ensure quiet, cool, and efcient
operation.
ASUS Express Gate
With on 5 seconds boot-up time, the ASUS Express Gate allows you
to instantly surf the Internet without entering Windows or the Hard
Disk. You can now enjoy Skype, IM, YouTube, webmail and internet le
downloads and sharing whenever and whatever you want.
• ASUS Express Gate supports le uploading from SATA HDDs, ODDs and USB drives
and downloading to USB drives only.
• The actural boot time is subject to hardware conguration and product models.
AI NET2
AI NET2 remotely detects cable connection the second you turn on the
system, and any faulty connections are reported back up to 100 meters
at 1 meter accuracy.
Green ASUS
This motherboard and its packaging comply with the European Union’s
Restriction on the use of Hazardous Substances (RoHS). This is in line
with the ASUS vision of creating environment-friendly and recyclable
products/packaging to safeguard consumers’ health while minimizing
the impact on the environment.
C.P.R. (CPU Parameter Recall)
The BIOS C.P.R. feature automatically restores the CPU default
settings when the system hangs due to overclocking failure. C.P.R.
eliminates the need to open the system chassis and clear the
RTC data. Simply shut down and reboot the system, and the BIOS
automatically restores the CPU parameters to their default settings.
1-4 ASUS M3A78-CM

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.
Chapter 1: Product introduction 1-5

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.
1-6 ASUS M3A78-CM

1.5.3 Motherboard layout
1.5.4 Layout contents
Connectors/Jumpers/Slots Page Connectors/Jumpers/Slots Page
1. ATX power connectors
(24-pin EATXPWR, 4-pin ATX12V)
1-21 10. Serial port connector (10-1 pin COM1) 1-21
2. AM2/AM2+ CPU socket 1-8 11. System panel connector (20-8 pin PANEL) 1-23
3. CPU fan connector (4-pin CPU_FAN) 1-9 12. Floppy disk drive connector (34-1 pin
FLOPPY)
1-20
4. Power/Chassis fan connector (3-pin
CHA_FAN, PWR_FAN)
1-24 13. TPM connector (20-1 pin TPM) 1-25
5. DDR2 DIMM slots 1-11 14. Clear RTC RAM (CLRTC) 1-17
6. Serial ATA connectors (7-pin SATA1-6) 1-22 15. USB connectors (10-1 pin USB78, USB910,
USB1112)
1-24
7. Onboard LED 1-5 16. Optical drive audio connector (4-pin CD) 1-22
8. IDE connector (40-1 pin PRI_IDE) 1-20 17. Front panel audio connector (10-1 pin AAFP) 1-25
9. LPT connector (26-1 pin LPT) 1-26 18 Digital audio connector (4-1 pin SPDIF_OUT) 1-26
Chapter 1: Product introduction 1-7

1.6 Central Processing Unit (CPU)
The motherboard comes with an AM2+ / AM2 socket designed for AMD® AM2+ / AM2
Phenom™ FX / Phenom / Athlon™ / Sempron™ processor.
The AM2/AM2+ socket has a different pinout from the 940-pin socket designed for the AMD
Opteron™ processor. Use a CPU that is designed for the AM2/AM2+ socket.
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.
1-8 ASUS M3A78-CM

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!
Gold triangle
Small 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
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.
Chapter 1: Product introduction 1-9

1.6.2 Installing the heatsink and fan
Ensure that you use only AMD-certied 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 bracket lock
Retention Module Base
Your boxed CPU heatsink and fan assembly should come with installation instructions for
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.
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