Intel BOXDX79TO User manual

Intel® Desktop Board
DX79TO
Technical Product Specification
January 2012
Order Number: G44010-002
The Intel®Desktop Board DX79TO may contain design defects or errors known as errata that may cause the product to deviate from published
specifications. Current characterized errata are documented in the Intel Desktop Board DX79TO Specification Update.

ii
Revision History
Revision Revision History Date
-001 First release of the Intel®Desktop Board DX79TO Technical Product
Specification
November 2011
-002 Specification Changes January 2012
This product specification applies to only the standard Intel®Desktop Board DX79TO with BIOS
identifier SIX7910J.86A.
INFORMATION IN THIS DOCUMENT IS PROVIDED IN CONNECTION WITH INTEL®PRODUCTS. NO LICENSE,
EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS
GRANTED BY THIS DOCUMENT. EXCEPT AS PROVIDED IN INTEL’S TERMS AND CONDITIONS OF SALE FOR
SUCH PRODUCTS, INTEL ASSUMES NO LIABILITY WHATSOEVER, AND INTEL DISCLAIMS ANY EXPRESS OR
IMPLIED WARRANTY, RELATING TO SALE AND/OR USE OF INTEL PRODUCTS INCLUDING LIABILITY OR
WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT
OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. UNLESS OTHERWISE AGREED IN
WRITING BY INTEL, THE INTEL PRODUCTS ARE NOT DESIGNED NOR INTENDED FOR ANY APPLICATION IN
WHICH THE FAILURE OF THE INTEL PRODUCT COULD CREATE A SITUATION WHERE PERSONAL INJURY OR
DEATH MAY OCCUR.
All Intel®desktop boards are evaluated as Information Technology Equipment (I.T.E.) for use in personal
computers (PC) for installation in homes, offices, schools, computer rooms, and similar locations. The
suitability of this product for other PC or embedded non-PC applications or other environments, such as
medical, industrial, alarm systems, test equipment, etc. may not be supported without further evaluation by
Intel.
Intel Corporation may have patents or pending patent applications, trademarks, copyrights, or other
intellectual property rights that relate to the presented subject matter. The furnishing of documents and
other materials and information does not provide any license, express or implied, by estoppel or otherwise,
to any such patents, trademarks, copyrights, or other intellectual property rights.
Intel may make changes to specifications and product descriptions at any time, without notice.
Designers must not rely on the absence or characteristics of any features or instructions marked “reserved”
or “undefined.” Intel reserves these for future definition and shall have no responsibility whatsoever for
conflicts or incompatibilities arising from future changes to them.
Intel desktop boards may contain design defects or errors known as errata, which may cause the product to
deviate from published specifications. Current characterized errata are available on request.
Contact your local Intel sales office or your distributor to obtain the latest specifications before placing your
product order.
Intel, Intel Core, and Xeon are trademarks of Intel Corporation in the U.S. and/or other countries.
* Other names and brands may be claimed as the property of others.
Copyright ©2011-2012 Intel Corporation. All rights reserved.

iii
Board Identification Information
Basic Desktop Board DX79TO Identification Information
AA Revision BIOS Revision Notes
G28805-400 SIX7910J.86A.0281 1,2
Notes:
1. The AA number is found on a small label on the component side of the board.
2. The X79 PCH used on this AA revision consists of the following component:
Device Stepping S-Spec Numbers
82X79 PCH C0 SLJHW
Specification Changes or Clarifications
Table 1 indicates the Specification Changes or Specification Clarifications that apply to
the Intel®Desktop Board DX79TO.
Table 1. Specification Changes or Clarifications
Date Type of Change Description of Changes or Clarifications
January 2012 Spec Change Added Section 1.12.2.10 Power Supervisor
Errata
Current characterized errata, if any, are documented in a separate Specification
Update. See http://developer.intel.com/products/desktop/motherboard/index.htm
for the latest documentation.

Intel Desktop Board DX79TO Technical Product Specification
iv

v
Preface
This Technical Product Specification (TPS) specifies the board layout, components,
connectors, power and environmental requirements, and the BIOS for the
Intel®Desktop Board DX79TO.
Intended Audience
The TPS is intended to provide detailed, technical information about the Intel Desktop
Board DX79TO and its components to the vendors, system integrators, and other
engineers and technicians who need this level of information. It is specifically not
intended for general audiences.
What This Document Contains
Chapter Description
1 A description of the hardware used on the Intel Desktop Board DX79TO
2 A map of the resources of the Intel Desktop Board
3 The features supported by the BIOS Setup program
4 A description of the BIOS error messages, beep codes, and POST codes
5 Regulatory compliance and battery disposal information
Typographical Conventions
This section contains information about the conventions used in this specification. Not
all of these symbols and abbreviations appear in all specifications of this type.
Notes, Cautions, and Warnings
NOTE
Notes call attention to important information.
CAUTION
Cautions are included to help you avoid damaging hardware or losing data.

Intel Desktop Board DX79TO Technical Product Specification
vi
Other Common Notation
# Used after a signal name to identify an active-low signal (such as USBP0#)
GB Gigabyte (1,073,741,824 bytes)
GB/s Gigabytes per second
Gb/s Gigabits per second
KB Kilobyte (1024 bytes)
Kbit Kilobit (1024 bits)
kbits/s 1000 bits per second
MB Megabyte (1,048,576 bytes)
MB/s Megabytes per second
Mbit Megabit (1,048,576 bits)
Mbits/s Megabits per second
xxh An address or data value ending with a lowercase h indicates a hexadecimal value.
x.x V Volts. Voltages are DC unless otherwise specified.
* This symbol is used to indicate third-party brands and names that are the property of their
respective owners.

vii
Contents
1Product Description
1.1Overview........................................................................................ 11
1.1.1Feature Summary ................................................................ 11
1.1.2Board Layout
....................................................................... 13
1.1.3Block Diagram ..................................................................... 15
1.2Legacy Considerations...................................................................... 16
1.3Online Support................................................................................ 16
1.4Processor ....................................................................................... 16
1.4.1PCI Express x16 Graphics
...................................................... 17
1.5System Memory .............................................................................. 17
1.5.1Memory Configurations ......................................................... 19
1.6Intel®X79 Express Chipset ............................................................... 21
1.6.1USB ................................................................................... 21
1.6.2SATA Interfaces ................................................................... 21
1.7Real-Time Clock Subsystem .............................................................. 23
1.8Legacy I/O Controller
....................................................................... 23
1.8.1Consumer Infrared (CIR)
....................................................... 23
1.9Audio Subsystem............................................................................. 24
1.9.1Audio Subsystem Software .................................................... 24
1.9.2Audio Subsystem Components ............................................... 24
1.10LAN Subsystem
............................................................................... 26
1.10.1Intel®82579L Gigabit Ethernet Controller ................................ 26
1.10.2LAN Subsystem Software....................................................... 27
1.10.3RJ-45 LAN Connector with Integrated LEDs .............................. 27
1.11Hardware Management Subsystem .................................................... 28
1.11.1Hardware Monitoring and Fan Control...................................... 28
1.11.2Fan Monitoring
..................................................................... 28
1.11.3Chassis Intrusion and Detection.............................................. 28
1.11.4Thermal Monitoring .............................................................. 29
1.12Power Management ......................................................................... 30
1.12.1ACPI................................................................................... 30
1.12.2Hardware Support ................................................................ 33
1.13Board Status LEDs
........................................................................... 37
1.14Onboard Power and Reset Buttons ..................................................... 39
1.15Trusted Platform Module (TPM).......................................................... 40

Intel Desktop Board DX79TO Technical Product Specification
viii
2Technical Reference
2.1Memory Resources .......................................................................... 41
2.1.1Addressable Memory............................................................. 41
2.1.2Memory Map........................................................................ 43
2.2Connectors and Headers................................................................... 43
2.2.1Back Panel Connectors
.......................................................... 44
2.2.2Component-side Connectors and Headers ................................ 46
2.3Jumper Block
.................................................................................. 55
2.4Mechanical Considerations ................................................................ 57
2.4.1Form Factor......................................................................... 57
2.5Electrical Considerations
................................................................... 58
2.5.1Power Supply Considerations ................................................. 58
2.5.2Fan Header Current Capability................................................ 59
2.5.3Add-in Board Considerations .................................................. 59
2.6Thermal Considerations
.................................................................... 60
2.7Reliability ....................................................................................... 62
2.8Environmental ................................................................................ 62
3Overview of BIOS Features
3.1Introduction ................................................................................... 63
3.2BIOS Flash Memory Organization
....................................................... 64
3.3Resource Configuration .................................................................... 64
3.3.1PCI Autoconfiguration ........................................................... 64
3.4System Management BIOS (SMBIOS)................................................. 65
3.5Legacy USB Support ........................................................................ 65
3.6BIOS Updates ................................................................................. 66
3.6.1Language Support ................................................................ 66
3.6.2Custom Splash Screen .......................................................... 67
3.7BIOS Recovery................................................................................ 67
3.8Boot Options................................................................................... 68
3.8.1Optical Drive Boot ................................................................ 68
3.8.2Network Boot....................................................................... 68
3.8.3Booting Without Attached Devices........................................... 68
3.8.4Changing the Default Boot Device During POST ........................ 68
3.9Adjusting Boot Speed....................................................................... 69
3.9.1Peripheral Selection and Configuration..................................... 69
3.9.2BIOS Boot Optimizations ....................................................... 69
3.10BIOS Security Features .................................................................... 70
3.11BIOS Performance Features .............................................................. 71
4Error Messages and Beep Codes
4.1Speaker ......................................................................................... 73
4.2BIOS Beep Codes ............................................................................ 73
4.3Front-panel Power LED Blink Codes
.................................................... 74
4.4BIOS Error Messages ....................................................................... 74
4.5Port 80h POST Codes ....................................................................... 75

Contents
ix
5Regulatory Compliance and Battery Disposal Information
5.1Regulatory Compliance..................................................................... 81
5.1.1Safety Standards.................................................................. 81
5.1.2European Union Declaration of Conformity Statement
................ 82
5.1.3Product Ecology Statements................................................... 83
5.1.4EMC Regulations .................................................................. 85
5.1.5ENERGY STAR* 5.0, e-Standby, and ErP Compliance ................. 88
5.1.6Regulatory Compliance Marks (Board Level)
............................. 89
5.2Battery Disposal Information............................................................. 90
Figures
1. Major Board Components.................................................................. 13
2. Block Diagram ................................................................................ 15
3. Memory Channel and DIMM Configuration ........................................... 20
4. Back Panel Audio Connectors ............................................................ 25
5. LAN Connector LED Locations............................................................ 27
6. Thermal Sensors and Fan Headers ..................................................... 29
7. Location of Board Status LEDs........................................................... 37
8. Location of the Onboard Power and Reset Buttons
................................ 39
9. Detailed System Memory Address Map ............................................... 42
10. Back Panel Connectors ..................................................................... 44
11. I/O Shield Reference Diagram ........................................................... 45
12. Component-side Connectors and Headers ........................................... 46
13. Connection Diagram for Front Panel Header ........................................ 52
14. Connection Diagram for Front Panel USB 2.0 Headers
........................... 54
15. Location of the Jumper Block............................................................. 55
16. Board Dimensions ........................................................................... 57
17. Localized High Temperature Zones..................................................... 61
Tables
1. Specification Changes or Clarifications ..................................................iii
2. Feature Summary............................................................................ 11
3. Components Shown in Figure 1 ......................................................... 14
4. Supported Memory Configurations ..................................................... 18
5. Audio Jack Support.......................................................................... 24
6. LAN Connector LED States ................................................................ 27
7. Effects of Pressing the Power Switch .................................................. 30
8. Power States and Targeted System Power........................................... 31
9. Wake-up Devices and Events ............................................................ 32
10. Board Status LEDs........................................................................... 38
11. System Memory Map ....................................................................... 43
12. Component-side Connectors and Headers Shown in Figure 12................ 47
13. Front Panel Audio Header for Intel HD Audio........................................ 48
14. Front Panel Audio Header for AC ’97 Audio .......................................... 48
15. IEEE 1394a Header.......................................................................... 49

Intel Desktop Board DX79TO Technical Product Specification
x
16. SATA Connectors............................................................................. 49
17. USB 2.0 Headers ............................................................................. 49
18. Chassis Intrusion Header.................................................................. 49
19. Processor, Front and Rear Chassis, and Auxiliary (4-Pin) Fan Headers
..... 49
20. Back Panel CIR Emitter (Output) Header............................................. 50
21. Front Panel CIR Receiver (Input) Header............................................. 50
22. Processor Core Power Connector........................................................ 51
23. Main Power Connector...................................................................... 51
24. Front Panel Header .......................................................................... 52
25. States for a One-Color Power LED...................................................... 53
26. States for a Two-Color Power LED...................................................... 53
27. BIOS Setup Configuration Jumper Settings.......................................... 56
28. Recommended Power Supply Current Values ....................................... 58
29. Fan Header Current Capability........................................................... 59
30. Thermal Considerations for Components ............................................. 61
31. Environmental Specifications............................................................. 62
32. BIOS Setup Program Menu Bar.......................................................... 64
33. BIOS Setup Program Function Keys.................................................... 64
34. Acceptable Drives/Media Types for BIOS Recovery ............................... 67
35. Boot Device Menu Options ................................................................ 68
36. Supervisor and User Password Functions............................................. 70
37. BIOS Beep Codes ............................................................................ 73
38. Front-panel Power LED Blink Codes.................................................... 74
39. BIOS Error Messages ....................................................................... 74
40. Port 80h POST Code Ranges.............................................................. 75
41. Port 80h POST Codes ....................................................................... 76
42. Typical Port 80h POST Sequence........................................................ 80
43. Safety Standards............................................................................. 81
44. EMC Regulations ............................................................................. 85
45. Regulatory Compliance Marks............................................................ 89

11
1Product Description
1.1 Overview
1.1.1 Feature Summary
Table 2 summarizes the major features of the board.
Table 2. Feature Summary
Form Factor ATX (12.00 inches by 9.60 inches [304.80 millimeters by 243.84 millimeters])
Processor •Intel®Core™ i7 and Intel®Xeon®processors in an LGA2011 socket:
―Two PCI Express 3.0 x16 graphics interfaces
―Four DDR3 memory channels (Quad Channel total of 8 DIMMs)
Memory •Eight 240-pin DDR3 SDRAM Dual Inline Memory Module (DIMM) sockets
arranged as four channels
•Support for DDR3 2400 MHz, 2133 MHz, 1866 MHz, 1600 MHz, 1333 MHz, and
1066 MHz DIMMs
•Support for 1 Gb, 2 Gb, and 4 Gb memory technology
•Support for up to 64 GB of system memory with eight DIMMs using 4 Gb
memory technology
•Support for non-ECC and ECC memory
•Support for 1.35 V low voltage JEDEC memory
•Support for XMP memory
•Support for manual memory over clocking (voltage, clock, ratio)
Chipset Intel®X79 Express Chipset consisting of the Intel®X79 Platform Controller
Hub (PCH)
Audio Intel®High Definition Audio subsystem using the Realtek* ALC892 audio codec
Legacy I/O Control Nuvoton* legacy I/O controller for Consumer Infrared (CIR)
Peripheral
Interfaces
•Two USB 3.0 ports are implemented with stacked back panel connectors (blue)
•Fourteen USB 2.0 ports:
―Six ports are implemented with stacked back panel connectors (black)
―Eight front panel ports implemented through four internal headers
•Two Serial ATA (SATA) 6.0 Gb/s interfaces through the Intel X79 Express
Chipset with Intel®Rapid Storage Technology RAID support (blue)
•Four internal SATA 3.0 Gb/s interfaces through the Intel X79 Express Chipset
with Intel Rapid Storage Technology RAID support (black)
•Two IEEE 1394a ports:
―One port via a back panel connector
―One port via a front-panel header (blue)
continued

Intel Desktop Board DX79TO Technical Product Specification
12
Table 2. Feature Summary (continued)
BIOS •Intel®BIOS resident in the SPI Flash device
•Support for Advanced Configuration and Power Interface (ACPI), Plug and Play,
and SMBIOS
•Fast Boot
•Support for advanced over clocking
Instantly Available
PC Technology
•Support for PCI* Local Bus Specification Revision 2.2
•Support for PCI Express* Revision 3.0
•Suspend to RAM support
•Wake on PCI, PCI Express, LAN, front panel, CIR, and USB ports
LAN Support Gigabit (10/100/1000 Mbits/s) LAN subsystem using the Intel
®
82579L Gigabit
Ethernet Controller
Expansion
Capabilities
•Two PCI Express 3.0 x16 connectors
•Three PCI Express 2.0 x1 bus add-in card connectors from the PCH
•One Conventional PCI bus add-in card connector from the PCH
Hardware Monitor
Subsystem
•Hardware monitoring and fan control through the Nuvoton I/O controller
•Voltage sense to detect out of range power supply voltages
•Thermal sense to detect out of range thermal values
•Four fan headers using PWM control
•Four fan sense inputs used to monitor fan activity
•Fan speed control using voltage control (4-pin fan headers for processor, front,
rear, and auxiliary) with selectable support in BIOS for 3 wire fans
•Support for Platform Environmental Control Interface (PECI)

Product Description
13
1.1.2 Board Layout
Figure 1 shows the location of the major components on Intel Desktop Board DX79TO.
Figure 1. Major Board Components
Table 3 lists the components identified in Figure 1.

Intel Desktop Board DX79TO Technical Product Specification
14
Table 3. Components Shown in Figure 1
Label Description
A Front panel audio header
B PCI Express x1 add-in card connector
C PCI Express x1 add-in card connector
D Piezoelectric speaker
E Conventional PCI add-in card connector
F PCI Express 3.0 x16 add-in card connector
G PCI Express x1 add-in card connector
H PCI Express 3.0 x16 add-in card connector
I Rear chassis fan header
J Battery
K Back panel connectors
L Processor fan header
M DIMM 1 (Channel A, DIMM 0)
N DIMM 5 (Channel B, DIMM 0)
O DIMM 2 (Channel A, DIMM 1)
P DIMM 6 (Channel B, DIMM 1)
Q LGA2011 processor socket
R 12 V processor core voltage connector (2 x 4 pin)
S DIMM 8 (Channel D, DIMM 1)
T DIMM 4 (Channel C, DIMM 1)
U DIMM 7 (Channel D, DIMM 0)
V DIMM 3 (Channel C, DIMM 0)
W Main power connector (2 x 12 pin)
X Front chassis fan header
Y 3.0 Gb/s SATA connectors (black) and 6.0 Gb/s SATA connectors (blue)
Z Intel X79 Express Chipset
AA Front panel USB 2.0 headers (4)
BB Consumer IR emitter (output) header
CC BIOS Setup configuration jumper block
DD Power Fault LED
EE Alternate front panel power LED header
FF Consumer IR receiver (input) header
GG Voltage measurement test points
HH Front panel header
II Post Code LED display
JJ Front panel IEEE 1394a header
KK Onboard Reset button
LL Onboard Power button
MM Chassis intrusion header
NN Auxiliary fan header
OO Board Status LEDs

Product Description
15
1.1.3 Block Diagram
Figure 2 is a block diagram of the major functional areas of the board.
Figure 2. Block Diagram

Intel Desktop Board DX79TO Technical Product Specification
16
1.2 Legacy Considerations
This board differs from other Intel Desktop Board products, with specific changes
including (but not limited to) the following:
•No parallel port connector
•No floppy drive connector
•No PS/2 connectors
1.3 Online Support
To find information about… Visit this World Wide Web site:
Intel Desktop Board DX79TO http://www.intel.com/products/motherboard/index.htm
Desktop Board Support http://www.intel.com/p/en_US/support?iid=hdr+support
Available configurations for the Intel
Desktop Board DX79TO
http://ark.intel.com
Supported processors http://processormatch.intel.com
Chipset information http://www.intel.com/products/desktop/chipsets/index.htm
BIOS and driver updates http://downloadcenter.intel.com
Tested memory http://www.intel.com/support/motherboards/desktop/sb/CS-
025414.htm
Integration information http://www.intel.com/support/go/buildit
1.4 Processor
The board is designed to support Intel Core i7 and Intel Xeon processors in an
LGA2011 socket
Other processors may be supported in the future. This board is designed to support
processors with a maximum wattage of 130 W with margin to allow for greater than
200 W operation. The processors listed above are only supported when falling within
the wattage requirements of the Intel Desktop Board DX79TO. See the Intel web site
listed below for the most up-to-date list of supported processors.
For information about… Refer to:
Supported processors http://processormatch.intel.com
CAUTION
Use only the processors listed on the web site above. Use of unsupported processors
can damage the board, the processor, and the power supply.
NOTE
This board has specific requirements for providing power to the processor. Refer to
Section 2.5.1 on page 58 for information on power supply requirements for this board.

Product Description
17
1.4.1 PCI Express x16 Graphics
Intel Core i7 and Intel Xeon processors in an LGA2011 package support PCI Express
add-in graphics cards via the board’s PCI Express x16 connectors. These processors
support the following generations of PCI Express:
•PCI Express 3.0 with a raw bit rate of 8.0 GT/s results in an effective bandwidth of
8.0 Gb/s each direction per lane. The maximum theoretical bandwidth of the x16
interface is 16 GB/s in each direction, simultaneously, for a bandwidth of 32 GB/s.
•PCI Express 2.x with a raw bit rate of 5.0 GT/s results in an effective bandwidth of
4.0 Gb/s each direction per lane. The maximum theoretical bandwidth of the x16
interface is 8 GB/s in each direction, simultaneously, for a bandwidth of 16 GB/s.
•PCI Express 1.x with a raw bit rate of 2.5 GT/s results in an effective bandwidth of
2.0 Gb/s each direction per lane. The maximum theoretical bandwidth of the x16
interface is 4 GB/s in each direction, simultaneously, for a bandwidth of 8 GB/s.
For information about Refer to
PCI Express technology http://www.pcisig.com
1.5 System Memory
The board has eight DIMM sockets and supports the following memory features:
•1.35 V DDR3 SDRAM DIMMs (JEDEC Specification)
•Four independent memory channels with interleaved mode support
•Unbuffered, single-sided or double-sided DIMMs with the following restriction:
Double-sided DIMMs with x16 organization are not supported.
•64 GB maximum total system memory (using 4 Gb memory technology). Refer to
Section 2.1.1 on page 41 for information on the total amount of addressable
memory.
•Minimum total system memory: 1 GB using 512 MB x16 module
•Non-ECC and ECC DIMMs
•Serial Presence Detect
•DDR3 2400 MHz, 2133 MHz, 1866 MHz, 1600 MHz, 1333 MHz, and 1066 MHz
SDRAM DIMMs
•XMP performance profile support for memory speeds above 1600 MHz
•Full support for over clocking memory (see
www.intel.com/support/motherboards/desktop/sb/CS-031689.htm for more
information about over clocking)
•DIMM slots are numbered in installation order
NOTE
To be fully compliant with all applicable DDR SDRAM memory specifications, the board
should be populated with DIMMs that support the Serial Presence Detect (SPD) data
structure. This allows the BIOS to read the SPD data and program the chipset to
accurately configure memory settings for optimum performance.

Intel Desktop Board DX79TO Technical Product Specification
18
CAUTION
1.5 V is the recommended and default setting for DDR3 memory voltage. The other
memory voltage settings in the BIOS Setup program are provided for performance
tuning purposes only. Altering the memory voltage may (i) reduce system stability
and the useful life of the system, memory, and processor; (ii) cause the processor and
other system components to fail; (iii) cause reductions in system performance; (iv)
cause additional heat or other damage; and (v) affect system data integrity.
Intel has not tested and does not warranty the operation of the processor beyond its
specifications. For information on the processor warranty, refer to
http://www.intel.com/support/processors/sb/CS-
020033.htm?wapkw=(processor+warranty).
Intel assumes no responsibility that the memory installed on the desktop board, if
used with altered clock frequencies and/or voltages, will be fit for any particular
purpose. Check with the memory manufacturer for warranty terms and additional
details.
Table 4 lists the supported DIMM configurations.
Table 4. Supported Memory Configurations
DIMM
Capacity Configuration (Note)
SDRAM
Density
SDRAM Organization
Front-side/Back-side
Number of SDRAM
Devices
512 MB SS 1 Gbit 64 M x16/empty 4
1024 MB SS 1 Gbit 128 M x8/empty 8
1024 MB SS 2 Gbit 128 M x16/empty 4
2048 MB DS 1 Gbit 128 M x8/128 M x8 16
2048 MB SS 2 Gbit 128 M x16/empty 8
4096 MB DS 2 Gbit 256 M x8/256 M x8 16
4096 MB SS 4 Gbit 512 M x8/empty 8
8192 MB DS 4 Gbit 512 M x8/512 M x8 16
Note: “DS” refers to double-sided memory modules (containing two rows of SDRAM) and “SS” refers to
single-sided memory modules (containing one row of SDRAM).
For information about… Refer to:
Tested Memory http://support.intel.com/support/motherboards/desktop/sb/CS-
025414.htm
XMP Tested Memory http://www.intel.com/personal/gaming/extremememory.htm

Product Description
19
1.5.1 Memory Configurations
The Intel Core i7 and Intel Xeon processors support the following types of memory
organization:
•Quad channel (Interleaved) mode. This mode offers the highest throughput for
real world applications.
•Tri channel (Interleaved) mode. Tri channel mode is enabled when the installed
memory capacities of any three DIMM channels are equal.
•Dual channel (Interleaved) mode. Dual channel mode is enabled when the
installed memory capacities of both DIMM channels are equal. Technology and
device width can vary from one channel to the other but the installed memory
capacity for each channel must be equal. If different speed DIMMs are used
between channels, the slowest memory timing will be used.
•Single channel (Asymmetric) mode. This mode is equivalent to single channel
bandwidth operation for real world applications. This mode is used when only a
single DIMM is installed or the memory capacities are unequal. Technology and
device width can vary from one channel to the other. If different speed DIMMs are
used between channels, the slowest memory timing will be used.
For information about… Refer to:
Memory Configuration Examples http://www.intel.com/support/motherboards/desktop/sb/cs-
011965.htm

Intel Desktop Board DX79TO Technical Product Specification
20
Figure 3 illustrates the memory channel and DIMM configuration.
Figure 3. Memory Channel and DIMM Configuration
NOTE
For best memory performance always install memory into the blue DIMM memory
sockets if installing four DIMMs or less in your configuration.