Intel BLKD945GNTL - LGA775 1066 800FSB 4DDR2 A/V Lan SATA ATX 10Pack... Configuration guide

May 2005
Order Number: D14069-001US
The Intel®Desktop Board D945GNT 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 D945GNT Specification Update.
Intel®Desktop Board
D945GNT
Technical Product Specification

Revision History
Revision Revision History Date
-001 First release of the Intel®Desktop Board D945GNT Technical Product
Specification. May 2005
This product specification applies to only the standard Intel Desktop Board D945GNT with BIOS
identifier NT94510J.86A.
Changes to this specification will be published in the Intel Desktop Board D945GNT Specification
Update before being incorporated into a revision of this document.
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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
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Intel reserves these for future definition and shall have no responsibility whatsoever for conflicts or incompatibilities arising
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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.
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Copyright ©2005, Intel Corporation. All rights reserved.

iii
Preface
This Technical Product Specification (TPS) specifies the board layout, components, connectors,
power and environmental requirements, and the BIOS for the Intel®Desktop Board D945GNT. It
describes the standard product and available manufacturing options.
Intended Audience
The TPS is intended to provide detailed, technical information about the Desktop Board D945GNT
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 Desktop Board D945GNT
2 A map of the resources of the Desktop Board
3 The features supported by the BIOS Setup program
4 A description of the BIOS error messages, beep codes, and POST codes
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.
# INTEGRATOR’S NOTES
Integrator’s notes are used to call attention to information that may be useful to system integrators.
CAUTION
Cautions are included to help you avoid damaging hardware or losing data.
WARNING
Warnings indicate conditions, which if not observed, can cause personal injury.

Intel Desktop Board D945GNT Technical Product Specification
iv
Other Common Notation
# Used after a signal name to identify an active-low signal (such as USBP0#)
(NxnX) When used in the description of a component, N indicates component type, xn are the relative
coordinates of its location on the Desktop Board D945GNT, and X is the instance of the
particular part at that general location. For example, J5J1 is a connector, located at 5J. It is
the first connector in the 5J area.
GB Gigabyte (1,073,741,824 bytes)
GB/sec Gigabytes per second
Gbits/sec Gigabits per second
KB Kilobyte (1024 bytes)
Kbit Kilobit (1024 bits)
kbits/sec 1000 bits per second
MB Megabyte (1,048,576 bytes)
MB/sec Megabytes per second
Mbit Megabit (1,048,576 bits)
Mbit/sec 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.

v
Contents
1Product Description
1.1 Overview......................................................................................................................10
1.1.1 Feature Summary..........................................................................................10
1.1.2 Manufacturing Options ..................................................................................11
1.1.3 Board Layout.................................................................................................12
1.1.4 Block Diagram...............................................................................................14
1.2 Online Support.............................................................................................................15
1.3 Processor.....................................................................................................................15
1.4 System Memory...........................................................................................................16
1.4.1 Memory Configurations .................................................................................17
1.5 Intel®945G Chipset .....................................................................................................21
1.5.1 Intel 945G Graphics Subsystem....................................................................21
1.5.2 USB...............................................................................................................23
1.5.3 IDE Support...................................................................................................24
1.5.4 Real-Time Clock, CMOS SRAM, and Battery................................................26
1.6 PCI Express Connectors..............................................................................................26
1.7 IEEE-1394a Connectors (Optional)..............................................................................26
1.8 Legacy I/O Controller...................................................................................................27
1.8.1 Serial Port......................................................................................................27
1.8.2 Parallel Port...................................................................................................27
1.8.3 Diskette Drive Controller................................................................................27
1.8.4 Keyboard and Mouse Interface .....................................................................27
1.9 Audio Subsystem.........................................................................................................28
1.9.1 Audio Subsystem Software ...........................................................................28
1.9.2 Audio Connectors..........................................................................................28
1.9.3 8-Channel (7.1) Audio Subsystem.................................................................29
1.9.4 6-Channel (5.1) Audio Subsystem.................................................................31
1.10 LAN Subsystem ...........................................................................................................32
1.10.1 LAN Subsystem Software..............................................................................32
1.10.2 10/100 Mbits/sec LAN Subsystem.................................................................32
1.10.3 Gigabit LAN Subsystem ................................................................................33
1.10.4 Intel®Active Management Technology (Optional).........................................34
1.10.5 Alert Standard Format (ASF) Support (Optional) ..........................................36
1.11 Hardware Management Subsystem.............................................................................36
1.11.1 Hardware Monitoring and Fan Control ASIC.................................................37
1.11.2 Chassis Intrusion and Detection....................................................................37
1.11.3 Fan Monitoring...............................................................................................37
1.11.4 Thermal Monitoring........................................................................................38
1.12 Power Management.....................................................................................................39
1.12.1 ACPI..............................................................................................................39
1.12.2 Hardware Support .........................................................................................41
1.13 Trusted Platform Module (Optional).............................................................................45

Intel Desktop Board D945GNT Technical Product Specification
vi
2Technical Reference
2.1 Introduction ..................................................................................................................47
2.2 Memory Resources......................................................................................................47
2.2.1 Addressable Memory.....................................................................................47
2.2.2 Memory Map..................................................................................................49
2.3 DMA Channels.............................................................................................................49
2.4 Fixed I/O Map...............................................................................................................50
2.5 PCI Configuration Space Map......................................................................................51
2.6 Interrupts......................................................................................................................52
2.7 PCI Conventional Interrupt Routing Map .....................................................................53
2.8 Connectors...................................................................................................................55
2.8.1 Back Panel Connectors.................................................................................55
2.8.2 Component-side Connectors.........................................................................58
2.9 Jumper Block ...............................................................................................................67
2.10 Mechanical Considerations..........................................................................................68
2.10.1 Form Factor...................................................................................................68
2.10.2 I/O Shield.......................................................................................................69
2.11 Electrical Considerations..............................................................................................71
2.11.1 DC Loading....................................................................................................71
2.11.2 Add-in Board Considerations.........................................................................71
2.11.3 Fan Connector Current Capability.................................................................72
2.11.4 Power Supply Considerations .......................................................................72
2.12 Thermal Considerations...............................................................................................73
2.13 Reliability......................................................................................................................75
2.14 Environmental..............................................................................................................76
2.15 Regulatory Compliance................................................................................................77
2.15.1 Safety Regulations ........................................................................................77
2.15.2 EMC Regulations...........................................................................................77
2.15.3 European Union Declaration of Conformity Statement..................................78
2.15.4 Recycling Considerations..............................................................................79
2.15.5 Product Certification Markings (Board Level)................................................80
3Overview of BIOS Features
3.1 Introduction ..................................................................................................................81
3.2 BIOS Flash Memory Organization ...............................................................................82
3.3 Resource Configuration ...............................................................................................82
3.3.1 PCI Autoconfiguration....................................................................................82
3.3.2 PCI IDE Support............................................................................................82
3.4 System Management BIOS (SMBIOS) ........................................................................83
3.5 Legacy USB Support....................................................................................................83
3.6 BIOS Updates..............................................................................................................84
3.6.1 Language Support.........................................................................................84
3.6.2 Custom Splash Screen..................................................................................84
3.7 Boot Options ................................................................................................................85
3.7.1 CD-ROM Boot ...............................................................................................85
3.7.2 Network Boot.................................................................................................85
3.7.3 Booting Without Attached Devices................................................................85
3.7.4 Changing the Default Boot Device During POST..........................................85

Contents
vii
3.8 Adjusting Boot Speed...................................................................................................86
3.8.1 Peripheral Selection and Configuration.........................................................86
3.8.2 BIOS Boot Optimizations...............................................................................86
3.9 BIOS Security Features ...............................................................................................87
4Error Messages and Beep Codes
4.1 Speaker .......................................................................................................................89
4.2 BIOS Beep Codes........................................................................................................89
4.3 BIOS Error Messages..................................................................................................89
4.4 Port 80h POST Codes .................................................................................................90
Figures
1. Board Components......................................................................................................12
2. Block Diagram..............................................................................................................14
3. Memory Channel and DIMM Configuration..................................................................17
4. Dual Channel (Interleaved) Mode Configuration with Two DIMMs ..............................18
5. Dual Channel (Interleaved) Mode Configuration with Three DIMMs............................18
6. Dual Channel (Interleaved) Mode Configuration with Four DIMMs..............................19
7. Single Channel (Asymmetric) Mode Configuration with One DIMM.............................20
8. Single Channel (Asymmetric) Mode Configuration with Three DIMMs........................20
9. Front/Back Panel Audio Connector Options for 8-Channel (7.1) Audio Subsystem....29
10. 8-channel (7.1) Audio Subsystem Block Diagram........................................................30
11. Front/Back Panel Audio Connector Options for 6-Channel (5.1) Audio Subsystem....31
12. 6-Channel (5.1) Audio Subsystem Block Diagram.......................................................31
13. LAN Connector LED Locations....................................................................................33
14. LAN Connector LED Locations....................................................................................34
15. Thermal Sensors and Fan Connectors........................................................................38
16. Location of the Standby Power Indicator LED .............................................................44
17. Detailed System Memory Address Map.......................................................................48
18. Back Panel Connectors for 8-Channel (7.1) Audio Subsystem ...................................56
19. Back Panel Connectors for 6-Channel (5.1) Audio Subsystem ...................................57
20. Component-side Connectors .......................................................................................58
21. Connection Diagram for Front Panel Connector..........................................................64
22. Connection Diagram for Front Panel USB Connectors................................................66
23. Connection Diagram for IEEE 1394a Connectors........................................................66
24. Location of the Jumper Block.......................................................................................67
25. Board Dimensions........................................................................................................68
26. I/O Shield Dimensions for Boards with the 8-Channel (7.1) Audio Subsystem............69
27. I/O Shield Dimensions for Boards with the 6-Channel (5.1) Audio Subsystem............70
28. Processor Heatsink for Omni-directional Airflow..........................................................73
29. Localized High Temperature Zones.............................................................................74
Tables
1. Feature Summary ........................................................................................................10
2. Manufacturing Options.................................................................................................11
3. Board Components Shown in Figure 1........................................................................13
4. Supported Memory Configurations ..............................................................................16
5. LAN Connector LED States .........................................................................................33

Intel Desktop Board D945GNT Technical Product Specification
viii
6. LAN Connector LED States .........................................................................................34
7. Effects of Pressing the Power Switch ..........................................................................39
8. Power States and Targeted System Power.................................................................40
9. Wake-up Devices and Events......................................................................................41
10. System Memory Map ...................................................................................................49
11. DMA Channels.............................................................................................................49
12. I/O Map ........................................................................................................................50
13. PCI Configuration Space Map......................................................................................51
14. Interrupts......................................................................................................................52
15. PCI Interrupt Routing Map ...........................................................................................54
16. Back Panel Connectors Shown in Figure 18................................................................56
17. Back Panel Connectors Shown in Figure 19................................................................57
18. Component-side Connectors Shown in Figure 20 .......................................................59
19. Front Panel Audio Connector.......................................................................................60
20. Chassis Intrusion Connector........................................................................................60
21. SCSI Hard Drive Activity LED Connector (Optional)....................................................60
22. Serial ATA Connectors.................................................................................................60
23. Processor Fan Connector............................................................................................61
24. Front and Rear Chassis Fan Connectors.....................................................................61
25. Auxiliary Fan Connector (optional)...............................................................................61
26. Main Power Connector.................................................................................................62
27. ATX12V Power Connector...........................................................................................62
28. Auxiliary Front Panel Power/Sleep LED Connector.....................................................63
29. Front Panel Connector.................................................................................................64
30. States for a One-Color Power LED..............................................................................65
31. States for a Two-Color Power LED..............................................................................65
32. BIOS Setup Configuration Jumper Settings.................................................................67
33. DC Loading Characteristics .........................................................................................71
34. Fan Connector Current Capability................................................................................72
35. Thermal Considerations for Components ....................................................................75
36. Environmental Specifications.......................................................................................76
37. Safety Regulations.......................................................................................................77
38. EMC Regulations.........................................................................................................77
39. Product Certification Markings.....................................................................................80
40. BIOS Setup Program Menu Bar...................................................................................82
41. BIOS Setup Program Function Keys............................................................................82
42. Boot Device Menu Options ..........................................................................................85
43. Supervisor and User Password Functions...................................................................87
44. Beep Codes .................................................................................................................89
45. BIOS Error Messages..................................................................................................89
46. Port 80h POST Code Ranges......................................................................................90
47. Port 80h POST Codes .................................................................................................91
48. Typical Port 80h POST Sequence...............................................................................94

9
1 Product Description
What This Chapter Contains
1.1 Overview......................................................................................................................10
1.2 Online Support.............................................................................................................15
1.3 Processor.....................................................................................................................15
1.4 System Memory...........................................................................................................16
1.5 Intel®945G Chipset .....................................................................................................21
1.6 PCI Express Connectors..............................................................................................26
1.7 IEEE-1394a Connectors (Optional)..............................................................................26
1.8 Legacy I/O Controller...................................................................................................27
1.9 Audio Subsystem.........................................................................................................28
1.10 LAN Subsystem ...........................................................................................................32
1.11 Hardware Management Subsystem.............................................................................36
1.12 Power Management.....................................................................................................39
1.13 Trusted Platform Module (Optional).............................................................................45

Intel Desktop Board D945GNT Technical Product Specification
10
1.1 Overview
1.1.1 Feature Summary
Table 1 summarizes the major features of the board.
Table 1. Feature Summary
Form Factor ATX (12.00 inches by 9.60 inches [304.80 millimeters by 243.84 millimeters])
Processor Support for an Intel®Pentium®4 processor in an LGA775 socket with a 1066, 800,
or 533 MHz system bus
Memory •Four 240-pin DDR2 SDRAM Dual Inline Memory Module (DIMM) sockets
•Support for DDR2 667, DDR2 533, or DDR2 400 MHz DIMMs
•Support for up to 4 GB of system memory
Chipset Intel®945G Chipset, consisting of:
•Intel®82945G Graphics Memory Controller Hub (GMCH)
•Intel®82801G I/O Controller Hub (ICH7)
Video Intel® GMA950 onboard graphics subsystem
Audio Refer to Table 2 on page 11 for a description of audio subsystem options
Legacy I/O Control Legacy I/O controller for diskette drive, serial, parallel, and PS/2* ports
USB Support for USB 2.0 devices
Peripheral
Interfaces
•Eight USB ports
•One serial port
•One parallel port
•Four Serial ATA interfaces
•One Parallel ATA IDE interface with UDMA 33, ATA-66/100 support
•One diskette drive interface
•PS/2 keyboard and mouse ports
LAN Support Refer to Table 2 on page 11 for a description of LAN subsystem options.
BIOS •Intel®BIOS (resident in the SPI Flash device)
•Support for Advanced Configuration and Power Interface (ACPI), Plug and Play,
and SMBIOS
Expansion
Capabilities
•Four PCI Conventional* bus connectors
•Two PCI Express* x1 bus add-in card connectors
•One PCI Express x16 bus add-in card connector
Instantly Available
PC Technology
•Support for PCI Local Bus Specification Revision 2.3
•Support for PCI Express Revision 1.0a
•Suspend to RAM support
•Wake on PCI, RS-232, front panel, PS/2 devices, and USB ports
Hardware Monitor
Subsystem
•Hardware monitoring and fan control ASIC
•Voltage sense to detect out of range power supply voltages
•Thermal sense to detect out of range thermal values
•Three fan connectors
•Three fan sense inputs used to monitor fan activity
•Fan speed control

Product Description
11
1.1.2 Manufacturing Options
Table 2 describes the manufacturing options. Not every manufacturing option is available in all
marketing channels. Please contact your Intel representative to determine which manufacturing
options are available to you.
Table 2. Manufacturing Options
Audio Subsystem Intel®High Definition Audio subsystem in one of the following configurations:
•8-channel (7.1) audio subsystem with five analog audio outputs and two S/PDIF
digital audio outputs (coaxial and optical) using the Sigmatel* 9223 audio codec
•6-channel (5.1) audio subsystem with three analog audio outputs using the
Sigmatel 9220 audio codec
Auxiliary fan
connector Additional fan connector for use in larger chassis
IEEE-1394a
Interface IEEE-1394a controller and three IEEE-1394a connectors (one back panel connector,
two front-panel connectors)
LAN subsystem The board provides one of the following:
•Gigabit (10/100/1000 Mbits/sec) LAN subsystem using the
Intel® 82573E/82573V/82574V Gigabit Ethernet Controller
•10/100 Mbits/sec LAN subsystem using the Intel®82562GX/82562GZ Platform
LAN Connect (PLC) device
SATA RAID Intel® 82801GR I/O Controller Hub (ICH7-R) for RAID support (levels 0,1, 0+1, and 5)
on the SATA interface
SCSI Hard Drive
Activity LED
Connector
Allows add-in hard drive controllers (SCSI or other) to use the same LED as the
onboard IDE controller
Trusted Platform
Module (TPM),
revision 1.2
A component that enhances platform security
For information about Refer to
Available configurations for the board Section 1.2, page 15

Intel Desktop Board D945GNT Technical Product Specification
12
1.1.3 Board Layout
Figure 1 shows the location of the major components.
I
DFGH
J
K
O
Q
S RTU
VW
X
Y
Z
GG
HH
EE
DD
CC
BB
EA
N
BC
M
L
OM17738
P
AA
FF
Figure 1. Board Components
Table 3 lists the components identified in Figure 1.

Product Description
13
Table 3. Board Components Shown in Figure 1
Item/callout
from Figure 1 Description
A Auxiliary fan connector (optional)
B Speaker
C PCI Express x1 bus add-in card connectors [2]
D Audio codec
E Front panel audio connector
F Ethernet device
G PCI Conventional bus add-in card connectors [2]
H PCI Express x16 bus add-in card connector
I Back panel connectors
J +12V power connector (ATX12V)
K Rear chassis fan connector
L LGA775 processor socket
M Intel 82945G GMCH
N Processor fan connector
O DIMM Channel A sockets [2]
P DIMM Channel B sockets [2]
Q SCSI LED connector (optional)
R Legacy I/O controller
S Power connector
T Diskette drive connector
U Parallel ATE IDE connector
V Battery
W Front chassis fan connector
X BIOS Setup configuration jumper block
Y Serial ATA connectors [4]
Z Auxiliary front panel power LED connector
AA Front panel connector
BB Front panel USB connectors [2]
CC Chassis intrusion connector
DD Intel 82801G I/O Controller Hub (ICH7)
EE SPI flash device
FF IEEE-1394a controller (optional)
GG Front panel IEEE-1394a connectors (optional) [2]
HH PCI Conventional bus add-in card connectors [2]

Intel Desktop Board D945GNT Technical Product Specification
14
1.1.4 Block Diagram
Figure 2 is a block diagram of the major functional areas.
Intel 945G Chipset
Intel 82801G
I/O Controller Hub
(ICH7)
Intel 82945G
Graphics and
Memory Controller
Hub (GMCH)
Serial Peripheral
Interface (SPI)
Flash Device
System Bus
(1066/800/533 MHz)
LGA775
Processor Socket
Parallel ATA
IDE Connector
Diskette Drive
Connector
Legacy
I/O
Controller PS/2 Keyboard
PS/2 Mouse
Parallel Port
Serial Port
Parallel ATA
IDE Interface
LPC
Bus
Hardware Monitoring
and Fan Control ASIC
OM17819
Audio
Codec
LAN
Connector
10/100
LAN PLC
(Optional)
PCI Express
x16 Interface
PCI Express
x16
Connector
= connector or socket
PCI Bus
SMBus
High Definition Audio Link
USB
Dual-Channel
Memory Bus
SMBus
PCI Slot 1
PCI Slot 2
PCI Slot 3
PCI Slot 4
Serial ATA IDE
Connectors (4)
Serial ATA
IDE Interface
VGA
Port Display Interface
Channel A
DIMMs (2)
Channel B
DIMMs (2)
Back Panel/Front Panel
USB Ports
DMI Interconnect
TPM Component
(Optional)
LPC
Bus
LAN Connect
Interface
PCI Express x1 Slot 1
PCI Express x1 Slot 2
PCI Express x1 Interface LAN
Connector
Gigabit Ethernet
Controller (Optional)
Line Out/Retasking Jack
Mic In
Line In/Retasking Jack
Mic In/Retasking Jack
S/PDIF (optional)
Surround L-R/
Retasking Jack (optional)
Center and LFE/
Retasking Jack (optional)
Line Out
PCI
Bus
IEEE-1394a Connectors
(optional)
IEEE-1394a
Controller
(optional)
Figure 2. Block Diagram

Product Description
15
1.2 Online Support
To find information about… Visit this World Wide Web site:
Intel Desktop Board D945GNT under
“Desktop Board Products” or “Desktop
Board Support”
http://www.intel.com/design/motherbd
http://support.intel.com/support/motherboards/desktop
Available configurations for the Desktop
Board D945GNT http://developer.intel.com/design/motherbd/nt/nt_available.htm
Processor data sheets http://www.intel.com/design/litcentr
ICH7 addressing http://developer.intel.com/products/chipsets
Custom splash screens http://intel.com/design/motherbd/gen_indx.htm
Audio software and utilities http://www.intel.com/design/motherbd
LAN software and drivers http://www.intel.com/design/motherbd
Supported video modes http://www.intel.com/design/motherbd/nt/nt_documentation.htm
Intel®Active Management Technology http://www.intel.com/technology/manage/iamt/index.htm
1.3 Processor
The board is designed to support Intel Pentium4 processors in an LGA775 processor socket with a
1066, 800, or 533 MHz system bus. 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://www.intel.com/design/motherbd/nt/nt_proc.htm
CAUTION
Use only the processors listed on web site above. Use of unsupported processors can damage the
board, the processor, and the power supply.
# INTEGRATOR’S NOTE
Use only ATX12V-compliant power supplies.
For information about Refer to
Power supply connectors Section 2.8.2.2, page 62

Intel Desktop Board D945GNT Technical Product Specification
16
1.4 System Memory
The board has four DIMM sockets and support the following memory features:
•1.8 V (only) DDR2 SDRAM DIMMs with gold-plated contacts
•Unbuffered, single-sided or double-sided DIMMs with the following restriction:
Double-sided DIMMS with x16 organization are not supported.
•4 GB maximum total system memory. Refer to Section 2.2.1 on page 47 for information on the
total amount of addressable memory.
•Minimum total system memory: 128 MB
•Non-ECC DIMMs
•Serial Presence Detect
•DDR2 667, DDR2 533, or DDR2 400 MHz SDRAM DIMMs
NOTES
•Remove the PCI Express x16 video card before installing or upgrading memory to avoid
interference with the memory retention mechanism.
•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. If non-SPD memory is installed, the BIOS will
attempt to correctly configure the memory settings, but performance and reliability may be
impacted or the DIMMs may not function under the determined frequency.
Table 4 lists the supported DIMM configurations.
Table 4. Supported Memory Configurations
DIMM
Capacity Configuration SDRAM Density SDRAM Organization Front-side/Back-side Number of SDRAM Devices
128 MB SS 256 Mbit 16 M x 16/empty 4
256 MB SS 256 Mbit 32 M x 8/empty 8
256 MB SS 512 Mbit 32 M x 16/empty 4
512 MB DS 256 Mbit 32 M x 8/32 M x 8 16
512 MB SS 512 Mbit 64 M x 8/empty 8
512 MB SS 1 Gbit 64 M x 16/empty 4
1024 MB DS 512 Mbit 64 M x 8/64 M x 8 16
1024 MB SS 1 Gbit 128 M x 8/empty 8
2048 MB DS 1 Gbit 128 M x 8/128 M x 8 16
Note: In the second column, “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).
# INTEGRATOR’S NOTE
It is possible to install four 2048 MB (2 GB) modules for a total of 8 GB of system memory,
however, only 4 GB of address space is available. Refer to Section 2.2.1, on page 47 for additional
information on available memory.

Product Description
17
1.4.1 Memory Configurations
The Intel 82945G GMCH supports two types of memory organization:
•Dual channel (Interleaved) mode. This mode offers the highest throughput for real world
applications. 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.
Figure 3 illustrates the memory channel and DIMM configuration.
 NOTE
The DIMM0 sockets of both channels are blue. The DIMM1 sockets of both channels are black.
OM17739
Channel A, DIMM 0
Channel A, DIMM 1
Channel B, DIMM 0
Channel B, DIMM 1
Figure 3. Memory Channel and DIMM Configuration

Intel Desktop Board D945GNT Technical Product Specification
18
1.4.1.1 Dual Channel (Interleaved) Mode Configurations
Figure 4 shows a dual channel configuration using two DIMMs. In this example, the DIMM0
(blue) sockets of both channels are populated with identical DIMMs.
OM17123
Channel A, DIMM 0
Channel A, DIMM 1
Channel B, DIMM 0
Channel B, DIMM 1
1 GB
1 GB
Figure 4. Dual Channel (Interleaved) Mode Configuration with Two DIMMs
Figure 5 shows a dual channel configuration using three DIMMs. In this example, the combined
capacity of the two DIMMs in Channel A equal the capacity of the single DIMM in the DIMM0
(blue) socket of Channel B.
OM17122
Channel A, DIMM 0
Channel A, DIMM 1
Channel B, DIMM 0
Channel B, DIMM 1
256 MB
512 MB
256 MB
Figure 5. Dual Channel (Interleaved) Mode Configuration with Three DIMMs

Product Description
19
Figure 6 shows a dual channel configuration using four DIMMs. In this example, the combined
capacity of the two DIMMs in Channel A equal the combined capacity of the two DIMMs in
Channel B. Also, the DIMMs are matched between DIMM0 and DIMM1 of both channels.
OM17124
Channel A, DIMM 0
Channel A, DIMM 1
Channel B, DIMM 0
Channel B, DIMM 1
256 MB
256 MB
512 MB
512 MB
Figure 6. Dual Channel (Interleaved) Mode Configuration with Four DIMMs

Intel Desktop Board D945GNT Technical Product Specification
20
1.4.1.2 Single Channel (Asymmetric) Mode Configurations
 NOTE
Dual channel (Interleaved) mode configurations provide the highest memory throughput.
Figure 7 shows a single channel configuration using one DIMM. In this example, only the DIMM0
(blue) socket of Channel A is populated. Channel B is not populated.
OM17125
Channel A, DIMM 0
Channel A, DIMM 1
Channel B, DIMM 0
Channel B, DIMM 1
256 MB
Figure 7. Single Channel (Asymmetric) Mode Configuration with One DIMM
Figure 8 shows a single channel configuration using three DIMMs. In this example, the combined
capacity of the two DIMMs in Channel A does not equal the capacity of the single DIMM in the
DIMM0 (blue) socket of Channel B.
OM17126
Channel A, DIMM 0
Channel A, DIMM 1
Channel B, DIMM 0
Channel B, DIMM 1
256 MB
512 MB
512 MB
Figure 8. Single Channel (Asymmetric) Mode Configuration with Three DIMMs