Asus M3N78 SE User manual

Motherboard
M3N78 SE

ii
Copyright © 2008 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.
E4330
Second Edition V2
November 2008

iii
Contents
Notices......................................................................................................... vi
Safety information ..................................................................................... vii
About this guide ........................................................................................ vii
M3N78 SE 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 ..................................................................... 1-4
1.5 Motherboard overview................................................................. 1-5
1.5.1 Placement direction ........................................................ 1-5
1.5.2 Screw holes .................................................................... 1-5
1.5.3 Motherboard layout ......................................................... 1-6
1.5.4 Layout contents............................................................... 1-6
1.6 Central Processing Unit (CPU) ................................................... 1-7
1.6.1 Installing the CPU ........................................................... 1-7
1.6.2 Installing the heatsink and fan ........................................ 1-9
1.7 System memory ......................................................................... 1-10
1.7.1 Overview ....................................................................... 1-10
1.7.2 Memory congurations...................................................1-11
1.7.3 Installing a DIMM .......................................................... 1-13
1.7.4 Removing a DIMM ........................................................ 1-13
1.8 Expansion slots.......................................................................... 1-14
1.8.1 Installing an expansion card ......................................... 1-14
1.8.2 Conguring an expansion card ..................................... 1-14
1.8.3 PCI slots........................................................................ 1-14
1.8.4 PCI Express x1 slot....................................................... 1-14
1.8.5 PCI Express x16 slot..................................................... 1-14
1.9 Jumpers ...................................................................................... 1-15
1.10 Connectors ................................................................................. 1-16
1.10.1 Rear panel connectors.................................................. 1-16
1.10.2 Internal connectors ....................................................... 1-17

iv
Contents
1.11 Software support........................................................................ 1-24
1.11.1 Installing an operating system ...................................... 1-24
1.11.2 Support DVD information .............................................. 1-24
1.11.3 Creating a RAID driver disk .......................................... 1-25
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 Sub-menu 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............................................... 2-9
2.3.5 SATA 1~4 ...................................................................... 2-10
2.3.6 Storage Conguration ....................................................2-11
2.3.7 System Information ....................................................... 2-12
2.4 Advanced menu ......................................................................... 2-12
2.4.1 JumperFree Conguration ............................................ 2-12
2.4.2 CPU Conguration ........................................................ 2-14
2.4.3 Chipset.......................................................................... 2-15
2.4.5 PCI PnP ........................................................................ 2-16
2.4.4 Onboard Devices Conguration.................................... 2-16

v
Contents
2.4.6 USB Conguration ........................................................ 2-17
2.5 Power menu................................................................................ 2-18
2.5.1 Suspend Mode ............................................................. 2-18
2.5.2 ACPI
2.0 Support ......................................................... 2-18
2.5.3 ACPI APIC Support ...................................................... 2-18
2.5.4 APM Conguration........................................................ 2-18
2.5.5 Hardware Monitor ......................................................... 2-19
2.6 Boot menu .................................................................................. 2-20
2.6.1 Boot Device Priority ...................................................... 2-20
2.6.2 Boot Settings Conguration .......................................... 2-20
2.6.3 Security ......................................................................... 2-21
2.7 Tools menu ................................................................................. 2-22
2.7.1 ASUS EZ Flash 2.......................................................... 2-22
2.7.2 AI NET 2........................................................................ 2-23
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.
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.
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.
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.
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.

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. This chapter also lists the hardware setup procedures that you have to
perform when installing system components. It includes description of the jumpers and
connectors on the motherboard.
• 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
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
Conventions used in this guide
To ensure that you perform certain tasks properly, take note of the following symbols used
throughout this manual.
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 /iM3N78SE.ROM
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.

ix
M3N78 SE specications summary
(continued on the next page)
CPU AMD® Socket AM2+ / AM2 for AMD Phenom™FX / Phenom
/ Athlon™ / Sempron™ processor
AMD Cool ‘n’ Quiet™ Technology
AMD Live!™ Ready
Supports CPU up to 125W
Chipset Nvidia® nForce™ 720D
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
2 x 240-pin DIMM slots support unbuffered
ECC and non-ECC DDR2 1066/800/667/533MHz
memory modules
Supports up to 8GB system memory
* Refer to www.asus.com for the latest Memory QVL
(Qualied Vendors List).
* When you install a total memory of 4GB or more,
Windows® 32-bit operation system may only recognize
less than 3GB. Hence, a maximum of 3GB system
memory is recommended if you are using a Windows
32-bit operation system.
Expansion slots 1 x PCI Express™ x16 slot
2 x PCI Express™ x1 slots
3 x PCI 2.2 slots
Storage / RAID 1 x UltraDMA 133/100 connector
4 x Serial ATA 3Gb/s connectors
Nvidia® MediaShield™ RAID supports RAID 0, RAID 1,
RAID 0+1, RAID 5, and JBOD conguration
Audio ALC662 High Denition Audio 6-channel CODEC
Supports Jack-detection and Multi-streaming
Supports S/PDIF out interface
USB Supports up to 12 USB 2.0/1.1 ports (6 ports
at mid-board, 6 ports at back panel)
LAN Nvidia nForce built-in Gigabit MAC with external Realtek
8211CL-GR PHY
ASUS overclocking
features
SFS (Stepless Frequency Selection)
- HT tuning from 200MHz up to 550MHz
at 1MHz increment
- Memory tuning from 533MHz up to 1066MHz
- PCIe frequency tuning from 100MHz up to 150MHz
at 1MHz increment
Overclocking Protection
- ASUS C.P.R. (CPU Parameter Recall)

x
M3N78 SE specications summary
ASUS special features ASUS Quiet Thermal Solution
- ASUS Q-Fan
ASUS EZ DIY
- ASUS CrashFree BIOS3
- ASUS EZ Flash2
ASUS AI NET 2
ASUS MyLogo2
Back panel I/O ports 1 x PS/2 Keyboard/Mouse Combo port
1 x RJ45 port
6 x USB 2.0/1.1 ports
6-channel Audio I/O ports
1 x LPT port
1 x COM port
Internal I/O connectors 3 x USB 2.0/1.1 connectors support additional
6 USB 2.0/1.1 ports
1 x Floppy disk drive connector
4 x SATA connectors
1 x system panel connector
1 x CD audio-in connector
1 x S/PDIF Out connector
1 x Front panel audio connector
1x CPU Fan connectors
24-pin EATX power connector
4-pin ATX 12V power connector
BIOS 8Mb Flash ROM, AMI BIOS, PnP, DMI2.0, WfM2.0,
ACPI2.0, SM BIOS 2.5, ASUS EZ Flash 2
Accessories 1 x Serial ATA cable
1 x Serial ATA power cable
1 x UltraDMA 133/100/66 cable
1x IO Shield
User manual
Form Factor ATX form factor: 12’’ x 8.6’’ (30.5cm x 21.8cm)
Support DVD Drivers
ASUS Update
ASUS PC Probe II
Anti-Virus software (OEM version)
*Specications are subject to change without notice.

ASUS M3N78 SE 1-1
1.1 Welcome!
Thank you for buying an ASUS® M3N78 SE 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.
If any of the above items is damaged or missing, contact your retailer.
1.2 Package contents
Check your motherboard package for the following items.
Motherboard ASUS M3N78 SE motherboard
Cables 1 x Serial ATA cable
1 x Serial ATA power cable
1 x Ultra DMA 133/100/66 cable
Accessories 1 x I/O shield
Application DVD ASUS motherboard support DVD
Documentation User guide
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. See page 1-7 for details.
AMD®Socket AM2 Athlon™ / Sempron CPU support
The motherboard supports AMD® Socket AM2 Athlon™ / Sempron
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. See page 1-7 for details.
1.3 Special features
1.3.1 Product highlights

1-2 Chapter 1: Product introduction
NVIDIA®nForce™ 720D chipset
The NVIDIA® nForce 720D supports HyperTransport™3.0 interface,
PCI Express™ 2.0 bus architecture, and Serial ATA 3 GB/s devices. It
is optimized with AMD’s latest AM2+ and multi-core CPUs to provide
excellent system performance.
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.
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.
Native DDR2 1066 support
This motherboar dsupports native DDR2 1066. It provides faster data
transfer rate and more bandwidth to increase memory data transfer rate
and computing efciency, enhancing system performance in 3D graphics
and other memory demanding applications. See pages 1-10 for details.
Due to AM2+ CPU limitation, only one DDR2 1066 is supported per channel. When four
DDR2 1066 DIMMs are installed, all DIMMs run at 800MHz frequency by default for
system stability.
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. See page 1-16 for details.
PCI Express 2.0 support
This motherboard supports the latest PCIe 2.0 devices for double speed
and bandwidth which enhances system performance.
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
SB700 southbridge allows RAID 0, RAID 1, RAID 0+1, and RAID 5
congurations for Serial ATA drives.

ASUS M3N78 SE 1-3
High Denition Audio
The onboard 6-channel HD audio (High Denition Audio, previously
codenamed Azalia) CODEC enables high-quality 192KHz/24-bit audio
output, jack-detect feature, and multi-streaming technology. This enables
you do multiple tasks, such as talking to your partners on the headphone
while playing a multi-channel network game, on just one computer.
1.3.2 Innovative ASUS features
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.
ASUS MyLogo2™
Turn your favorite photos into 256-color boot logos to personalize your
system. See page 2-20 for details.
ASUS CrashFree BIOS 3
The ASUS CrashFree BIOS 3 allows you to restore corrupted BIOS data
from a USB ash disk containing the BIOS le. This utility saves you the
cost and hassle of buying a replacement BIOS chip. See page 2-5 for
details.
ASUS EZ Flash 2
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. See page 2-3 for
details.
CPU Parameter Recall (C.P.R)
When the system hangs due to overclocking failure, there is no need to
open the case to clear CMOS data. Just simply restart the system, the
BIOS would show the previous setting and then users can amend the
CPU setting again. See page 1-15 for details.

1-4 Chapter 1: Product introduction
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 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.
• Use a grounded wrist strap or touch a safely grounded object or a metal object, such
as the power supply case, before handling components 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.
M3N78 SE
SB_PWR
ON
Standy Power Powered Off
OFF
M3N78 SE Onboard LED

ASUS M3N78 SE 1-5
M3N78 SE
Do not overtighten the screws! Doing so can damage the motherboard.
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.
Place this side towards
the rear of the chassis.
1.5.2 Screw holes
Place six (6) screws into the holes indicated by circles to secure the motherboard to the
chassis.
1.5 Motherboard overview

1-6 Chapter 1: Product introduction
1.5.3 Motherboard layout
M3N78 SE
PCIEX16
PCIEX1_1
PCIEX1_2
PCI2
PCI3
PCI1
FLOPPY
USB910 USB78 USB1112
F_PANEL
SPDIF_OUT
AAFP
CD
ATX12V
EATXPWR
CPU_FAN
Lithium Cell
CMOS Power
Super
I/O
ALC
662
Realtek
8211CL
KB_USB56
8Mb
BIOS
SB_PWR CLRTC
SPEAKER
21.8cm(8.6in)
NVIDIA®
MCP78D
DDR2 DIMM_A1 (64bit, 240-pin module)
SOCKET AM2
DDR2 DIMM_B1 (64bit, 240-pin module)
SATA4
SATA3
SATA2
SATA1
AUDIO
LPT
COM
LAN1_USB12
USB34
30.5cm(12.0in)
PRI_IDE
1 2 3 4
5
6
7
8
9
10111213
2
14
Connectors/Jumpers/Slots Page Connectors/Jumpers/Slots Page
1. AM2+ CPU Socket 1-7 8. Internal speaker connector (4-pin SPEAKER) 1-18
2. ATX power connectors (24-pin EATXPWR, 4-pin ATX12V) 1-22 9. System panel connector (10-1 pin F_PANEL) 1-23
3. CPU fan connector (4-pin CPU_FAN) 1-8 10. Clear RTC RAM (3-pin CLRTC) 1-15
4. DDR2 DIMM slots 1-10 11. Floppy disk drive connector (34-1 pin FLOPPY) 1-17
5. Serial ATA connectors (7-pin SATA1, SATA2, SATA3, SATA4) 1-19 12. Optical drive audio connector (4-pin CD) 1-20
6. USB connectors (10-1 pin USB78, USB 910, USB1112) 1-20 13. Front panel audio connector (10-1 pin AAFP) 1-21
7. IDE connector (40-1 pin PRI_IDE) 1-18 14. Digital audio connector (4-1 pin SPDIF_OUT) 1-21
1.5.4 Layout contents

ASUS M3N78 SE 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. Ensure that you use a CPU that is designed for the AM2/AM2+
socket. The CPU ts in only one correct orientation. DO NOT force the CPU into the socket
to prevent bending the connectors on the socket and damaging the CPU!
1.6.1 Installing the CPU
To install a CPU:
1. Locate the CPU socket on the motherboard.
Make sure that the socket lever is lifted up to
a 90º angle; otherwise, the CPU will not t in
completely.
2. Unlock the socket by pressing the lever
sideways, then lift it up to a 90º angle.
Socket lever
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
M3N78 SE
M3N78 SE CPU socket 940

1-8 Chapter 1: Product introduction
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.
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.
CPU_FAN
CPU FAN PWM
CPU FAN IN
CPU FAN PWR
GND
M3N78 SE
M3N78 SE CPU fan connector

ASUS M3N78 SE 1-9
1.6.2 Installing the heatsink and fan
The AMD Phenom™ FX / Phenom / Athlon™ / Sempron™ processor requires a specially
designed heatsink and fan assembly to ensure optimum thermal condition and performance
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.
Ensure that you use only qualied heatsink and fan assembly.
• 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.
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.
1
34
5
2
CPU Fan
CPU Heatsink
Retention bracket
Retention bracket Retention Module Base

1-10 Chapter 1: Product introduction
3. Align the other end of the retention bracket (near the retention bracket lock) 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. Connect the CPU fan cable to the connector on the motherboard labeled CPU_FAN.
1.7 System memory
1.7.1 Overview
The motherboard comes with two 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 1 DIMM_A1
Channel 2 DIMM_B1
M3N78 SE
M3N78 SE 240-pin DDR2 DIMM sockets
DIMM_A1 DIMM_B1