Intel BLKD915GMHLK - LGA775 800FSB Dual DDR400 GIG Lan PCI Express mBTX... Configuration guide

December 2004
Order Number: C81296-001
The Intel®Desktop Board D915GMH 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 D915GMH Specification Update.
Intel®Desktop Board
D915GMH
Technical Product Specification

Revision History
Revision Revision History Date
-001 First release of the Intel®Desktop Board D915GMH Technical Product
Specification.
December 2004
This product specification applies to only standard Intel®Desktop Board D915GMH with BIOS
identifier EV91510A.86A.
Changes to this specification will be published in the Intel Desktop Board D915GMH Specification
Update before being incorporated into a revision of this document.
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
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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.
Copies of documents which have an ordering number and are referenced in this document, or other Intel literature, may be
obtained from:
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countries.
* Other names and brands may be claimed as the property of others.

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 D915GMH. It
describes the standard product and available manufacturing options.
Intended Audience
The TPS is intended to provide detailed, technical information about the Desktop Board D915GMH
and their 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 D915GMH
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 D915GMH 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 D915GMH, 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
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 PCI Bus Terminology Change...................................................................................... 11
1.2 Power Connector Terminology Change ....................................................................... 11
1.3 Overview ...................................................................................................................... 12
1.3.1 Feature Summary.......................................................................................... 12
1.3.2 Manufacturing Options .................................................................................. 13
1.3.3 Board Layout ................................................................................................. 14
1.3.4 Block Diagram ............................................................................................... 16
1.4 Online Support ............................................................................................................. 17
1.5 Processor ..................................................................................................................... 17
1.6 System Memory ........................................................................................................... 18
1.6.1 Memory Configurations ................................................................................. 20
1.7 Intel®915G Chipset ..................................................................................................... 24
1.7.1 Intel 915G Graphics Subsystem.................................................................... 24
1.7.2 USB ............................................................................................................... 26
1.7.3 IDE Support ................................................................................................... 26
1.7.4 Real-Time Clock, CMOS SRAM, and Battery................................................ 28
1.8 PCI Express Connectors.............................................................................................. 28
1.9 I/O Controller................................................................................................................ 29
1.9.1 Serial Port...................................................................................................... 29
1.9.2 Parallel Port ................................................................................................... 29
1.9.3 Diskette Drive Controller................................................................................ 29
1.9.4 Keyboard and Mouse Interface ..................................................................... 30
1.10 Audio Subsystem ......................................................................................................... 30
1.10.1 Audio Subsystem Software ........................................................................... 31
1.10.2 Audio Connectors .......................................................................................... 31
1.10.3 8-Channel (7.1) Audio Subsystem................................................................. 32
1.10.4 6-Channel (5.1) Audio Subsystem................................................................. 34
1.11 LAN Subsystem ........................................................................................................... 35
1.11.1 10/100 Mbits/sec LAN Subsystem................................................................. 35
1.11.2 Gigabit LAN Subsystem ................................................................................ 36
1.11.3 Alert Standard Format (ASF) Support ........................................................... 37
1.11.4 LAN Subsystem Software.............................................................................. 38
1.12 Hardware Management Subsystem............................................................................. 38
1.12.1 Hardware Monitoring and Fan Control ASIC ................................................. 38
1.12.2 Thermal Monitoring........................................................................................ 39
1.12.3 Fan Monitoring............................................................................................... 40
1.12.4 Chassis Intrusion and Detection....................................................................40
1.13 Power Management ..................................................................................................... 40
1.13.1 ACPI .............................................................................................................. 40
1.13.2 Hardware Support ......................................................................................... 42
1.14 Trusted Platform Module (Optional) ............................................................................. 46
1.14.1 System Requirements ................................................................................... 46
1.14.2 Warning of Potential Data Loss ..................................................................... 46

Intel Desktop Board D915GMH Technical Product Specification
vi
1.14.3 Security Precautions...................................................................................... 47
1.14.4 Trusted Platform Module Ownership ............................................................. 48
1.14.5 Enabling the Trusted Platform Module .......................................................... 49
1.14.6 Assuming Trusted Platform Module Ownership ............................................ 49
1.14.7 Recovery Procedures .................................................................................... 50
1.14.8 Clearing Trusted Platform Module Ownership............................................... 51
1.14.9 Software Support........................................................................................... 52
2Technical Reference
2.1 Introduction .................................................................................................................. 53
2.2 Memory Resources ...................................................................................................... 53
2.2.1 Addressable Memory..................................................................................... 53
2.2.2 Memory Map.................................................................................................. 55
2.3 DMA Channels ............................................................................................................. 55
2.4 Fixed I/O Map............................................................................................................... 56
2.5 PCI Configuration Space Map...................................................................................... 57
2.6 Interrupts ......................................................................................................................58
2.7 PCI Conventional Interrupt Routing Map ..................................................................... 59
2.8 Connectors................................................................................................................... 60
2.8.1 Back Panel Connectors ................................................................................. 60
2.8.2 Component-side Connectors......................................................................... 64
2.9 Jumper Block ............................................................................................................... 72
2.10 Mechanical Considerations .......................................................................................... 73
2.10.1 Form Factor ................................................................................................... 73
2.10.2 I/O Shield....................................................................................................... 74
2.11 Electrical Considerations.............................................................................................. 76
2.11.1 DC Loading.................................................................................................... 76
2.11.2 Add-in Board Considerations......................................................................... 76
2.11.3 Fan Connector Current Capability ................................................................. 76
2.11.4 Power Supply Considerations ....................................................................... 77
2.12 Thermal Considerations ............................................................................................... 77
2.13 Reliability...................................................................................................................... 79
2.14 Environmental .............................................................................................................. 80
2.15 Regulatory Compliance................................................................................................ 81
2.15.1 Safety Regulations ........................................................................................ 81
2.15.2 EMC Regulations........................................................................................... 81
2.15.3 European Union Declaration of Conformity Statement.................................. 82
2.15.4 Product Ecology Statements ......................................................................... 83
2.15.5 Product Certification Markings (Board Level) ................................................ 84
3Overview of BIOS Features
3.1 Introduction .................................................................................................................. 85
3.2 BIOS Flash Memory Organization ...............................................................................86
3.3 Resource Configuration ............................................................................................... 86
3.3.1 PCI Autoconfiguration.................................................................................... 86
3.3.2 PCI IDE Support ............................................................................................ 86
3.4 System Management BIOS (SMBIOS) ........................................................................ 87
3.5 Legacy USB Support.................................................................................................... 87

Contents
vii
3.6 BIOS Updates .............................................................................................................. 88
3.6.1 Language Support ......................................................................................... 88
3.6.2 Custom Splash Screen.................................................................................. 88
3.7 Boot Options ................................................................................................................ 89
3.7.1 CD-ROM Boot ............................................................................................... 89
3.7.2 Network Boot ................................................................................................. 89
3.7.3 Booting Without Attached Devices ................................................................ 89
3.7.4 Changing the Default Boot Device During POST .......................................... 89
3.8 Fast Booting Systems with Intel®Rapid BIOS Boot ....................................................90
3.8.1 Peripheral Selection and Configuration ......................................................... 90
3.8.2 Intel Rapid BIOS Boot ................................................................................... 90
3.9 BIOS Security Features ............................................................................................... 91
4Error Messages and Beep Codes
4.1 BIOS Error Messages .................................................................................................. 93
4.2 Port 80h POST Codes ................................................................................................. 95
4.3 Bus Initialization Checkpoints ......................................................................................99
4.4 Speaker...................................................................................................................... 100
4.5 BIOS Beep Codes...................................................................................................... 100
Figures
1. Board Components ...................................................................................................... 14
2. Block Diagram.............................................................................................................. 16
3. Memory Channel Configuration ................................................................................... 20
4. Dual Channel (Interleaved) Mode Configuration with Two DIMMs .............................. 21
5. Dual Channel (Interleaved) Mode Configuration with Three DIMMs............................ 21
6. Dual Channel (Interleaved) Mode Configuration with Four DIMMs.............................. 22
7. Single Channel (Asymmetric) Mode Configuration with One DIMM............................. 23
8. Single Channel (Asymmetric) Mode Configuration with Three DIMMs ........................23
9. Front/Back Panel Audio Connector Options for 8-Channel (7.1) Audio Subsystem .... 32
10. 8-channel (7.1) Audio Subsystem Block Diagram........................................................ 33
11. Front/Back Panel Audio Connector Options for 6-Channel (5.1) Audio Subsystem .... 34
12. 6-Channel (5.1) Audio Subsystem Block Diagram....................................................... 34
13. LAN Connector LED Locations .................................................................................... 35
14. LAN Connector LED Locations .................................................................................... 36
15. Thermal Monitoring ...................................................................................................... 39
16. Location of the Standby Power Indicator LED ............................................................. 45
17. Detailed System Memory Address Map....................................................................... 54
18. Back Panel Connectors for 8-Channel (7.1) Audio Subsystem ................................... 61
19. Back Panel Connectors for 6-Channel (5.1) Audio Subsystem ................................... 62
20. Component-side Connectors ....................................................................................... 64
21. Connection Diagram for Front Panel Connector .......................................................... 69
22. Connection Diagram for Front Panel USB Connectors................................................ 71
23. Connection Diagram for IEEE 1394a Connectors........................................................ 71
24. Location of the Jumper Block.......................................................................................72
25. Board Dimensions........................................................................................................ 73
26. I/O Shield Dimensions for Boards with the 8-channel (7.1) Audio Subsystem ............ 74

Intel Desktop Board D915GMH Technical Product Specification
viii
27. I/O Shield Dimensions for Boards with the 6-channel (5.1) Audio Subsystem ............ 75
28. Localized High Temperature Zones ............................................................................. 78
Tables
1. Feature Summary ........................................................................................................ 12
2. Manufacturing Options ................................................................................................. 13
3. Board Components Shown in Figure 1 ........................................................................ 15
4. Supported System Bus Frequency and Memory Speed Combinations ....................... 18
5. Supported Memory Configurations .............................................................................. 19
6. LAN Connector LED States ......................................................................................... 36
7. LAN Connector LED States ......................................................................................... 37
8. Effects of Pressing the Power Switch .......................................................................... 41
9. Power States and Targeted System Power ................................................................. 41
10. Wake-up Devices and Events ...................................................................................... 42
11. System Memory Map ................................................................................................... 55
12. DMA Channels ............................................................................................................. 55
13. I/O Map ........................................................................................................................ 56
14. PCI Configuration Space Map...................................................................................... 57
15. Interrupts ......................................................................................................................58
16. PCI Interrupt Routing Map ........................................................................................... 59
17. Back Panel Connectors Shown in Figure 18................................................................ 61
18. Back Panel Connectors Shown in Figure 19................................................................ 63
19. Component-side Connectors Shown in Figure 20 ....................................................... 65
20. S/PDIF Connector (Optional) ....................................................................................... 65
21. ATAPI CD-ROM Connector (Optional)......................................................................... 65
22. Front Panel Audio Connector.......................................................................................66
23. Front Chassis Fan and Rear Chassis Fan Connectors................................................ 66
24. Processor Fan Connector ............................................................................................ 66
25. Chassis Intrusion Connector ........................................................................................ 66
26. Serial ATA Connectors................................................................................................. 66
27. Main Power Connector................................................................................................. 67
28. Processor Core Power Connector ............................................................................... 68
29. Alternate Power Connector .......................................................................................... 68
30. Auxiliary Front Panel Power/Sleep LED Connector ..................................................... 69
31. Front Panel Connector ................................................................................................. 69
32. States for a One-Color Power LED .............................................................................. 70
33. States for a Two-Color Power LED .............................................................................. 70
34. BIOS Setup Configuration Jumper Settings................................................................. 72
35. DC Loading Characteristics ......................................................................................... 76
36. Fan Connector Current Capability................................................................................ 76
37. Thermal Considerations for Components .................................................................... 79
38. Environmental Specifications ....................................................................................... 80
39. Safety Regulations ....................................................................................................... 81
40. EMC Regulations ......................................................................................................... 81
41. Product Certification Markings ..................................................................................... 84
42. BIOS Setup Program Menu Bar................................................................................... 86
43. BIOS Setup Program Function Keys............................................................................ 86

Contents
ix
44. Boot Device Menu Options .......................................................................................... 89
45. Supervisor and User Password Functions ................................................................... 91
46. BIOS Error Messages .................................................................................................. 93
47. Uncompressed INIT Code Checkpoints....................................................................... 95
48. Boot Block Recovery Code Checkpoints ..................................................................... 95
49. Runtime Code Uncompressed in F000 Shadow RAM ................................................. 96
50. Bus Initialization Checkpoints ......................................................................................99
51. Upper Nibble High Byte Functions ............................................................................... 99
52. Lower Nibble High Byte Functions ............................................................................. 100
53. Beep Codes ............................................................................................................... 100

Intel Desktop Board D915GMH Technical Product Specification
x

11
1Product Description
What This Chapter Contains
1.1 PCI Bus Terminology Change...................................................................................... 11
1.2 Power Connector Terminology Change ....................................................................... 11
1.3 Overview ...................................................................................................................... 12
1.4 Online Support ............................................................................................................. 17
1.5 Processor ..................................................................................................................... 17
1.6 System Memory ........................................................................................................... 18
1.7 Intel®915G Chipset ..................................................................................................... 24
1.8 PCI Express Connectors.............................................................................................. 28
1.9 I/O Controller................................................................................................................ 29
1.10 Audio Subsystem ......................................................................................................... 30
1.11 LAN Subsystem ........................................................................................................... 35
1.12 Hardware Management Subsystem............................................................................. 38
1.13 Power Management ..................................................................................................... 40
1.14 Trusted Platform Module (Optional) ............................................................................. 46
1.1 PCI Bus Terminology Change
Previous generations of Intel®Desktop Boards used an add-in card connector referred to as PCI.
This generation of Intel Desktop Boards adds a new technology for add-in cards: PCI Express*.
The 32-bit parallel bus previously referred to as PCI is now called PCI Conventional.
1.2 Power Connector Terminology Change
Technical Product Specifications for ATX and microATX desktop boards referred to the 2 x 2
power connector as the ATX12V connector. With the arrival of BTX form factor desktop boards,
this connector will henceforth be referred to as the Processor Core Power connector.
For information about Refer to
The BTX form factor http://www.formfactors.org

Intel Desktop Board D915GMH Technical Product Specification
12
1.3 Overview
1.3.1 Feature Summary
Table 1 summarizes the major features of the Desktop Board D915GMH.
Table 1. Feature Summary
Form Factor microBTX Form Factor (10.50 inches by 10.40 inches [266.70 millimeters by
264.16 millimeters])
Processor Support for an Intel®Pentium®4 processor in an LGA775 socket with an 800 or
533 MHz system bus
Memory •Four DDR SDRAM Dual Inline Memory Module (DIMM) sockets
•Support for DDR 400 MHz and DDR 333 MHz DIMMs
•Support for up to 4 GB of system memory
Chipset Intel®915G Chipset, consisting of:
•Intel®82915G Graphics Memory Controller Hub (GMCH)
•Intel®82801FB I/O Controller Hub (ICH6)
•4 Mbit Firmware Hub (FWH)
Video Intel® GMA900 onboard graphics subsystem
I/O Control LPC Bus I/O controller
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
BIOS •Intel/AMI BIOS (resident in the 4 Mbit FWH)
•Support for Advanced Configuration and Power Interface (ACPI), Plug and Play,
and SMBIOS
Instantly Available
PC Technology
•Support for PCI Local Bus Specification Revision 2.2
•Support for PCI Express Revision 1.0a
•Suspend to RAM support
•Wake on PCI, RS-232, front panel, PS/2 devices, and USB ports
continued

Product Description
13
Table 1. Feature Summary (continued)
Expansion
Capabilities
•Two PCI Conventional bus add-in card connectors (SMBus routed to PCI
Conventional bus connector 2)
•One PCI Express x1 bus add-in card connector
•One PCI Express x16 bus add-in card connector
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
1.3.2 Manufacturing Options
Table 2 describes the manufacturing options on the Desktop Board D915GMH. 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
ATAPI CD-ROM
Connector
A connector for attaching an internal CD-ROM drive to the onboard audio subsystem
Audio Subsystem Intel®High Definition Audio subsystem in one of the following configurations:
•8-channel (7.1) audio subsystem with five analog audio outputs using the
Realtek ALC880 audio codec
•6-channel (5.1) audio subsystem with three analog audio outputs using the
Realtek ALC860 audio codec
IEEE-1394a
Interface
IEEE-1394a controller and two IEEE-1394a connectors (one back panel connector
and one front-panel connector)
LAN One of the following:
•10/100 Mbits/sec LAN subsystem using the Intel®82562EZ Platform LAN Connect
(PLC) device
•Gigabit (10/100/1000 Mbits/sec) LAN subsystem using the Marvell* Yukon*
88E8050 PCI Express Gigabit Ethernet Controller
RAID support RAID 0 and RAID 1 support with optional ICH6-R
Security Trusted Platform Module (TPM): a component that enhances platform security
S/PDIF Connector A 1 x 3 connector mounted on the component side of the board that provides digital
audio signals in S/PDIF format
For information about Refer to
Available configurations for the Desktop Board D915GMH Section 1.4, page 17

Intel Desktop Board D915GMH Technical Product Specification
14
1.3.3 Board Layout
Figure 1 shows the location of the major components on the Desktop Board D915GMH.
OM17544
Intel
R
82915G
(GMCH)
Intel
R
82801
(ICH)
A
BC
E
F
G
H
K
J
I
OOMM
N
V
D
RR
Q
U
S
L
T
PP
RJ45
Line In
X
W
Figure 1. Board Components

Product Description
15
Table 3 lists the components identified in Figure 1.
Table 3. Board Components Shown in Figure 1
Item/Callout
from Figure 1 Description
A Front panel audio connector
B Chassis intrusion connector
C Main power connector (2 x 12)
D Front Panel USB connectors
E PCI Express x1 connector
F PCI bus add-in card connectors
G PCI Express x16 connector
H Alternate power connector (1 x 4)
I Diskette drive connector
J BIOS Setup Configuration Jumper
K IEEE 1394a connectors (optional)
L Front chassis fan connector
M Front panel connector
N Alternate power LED connector
O Processor socket
P Processor core power connector (2 x 2)
Q Processor fan header (4-pin, fan speed control)
R DIMM sockets
S Battery
T IDE connector
U ATAPI CD-ROM connector (optional)
V Rear chassis fan connector
W S/PDIF connector (optional)
X Serial ATA connectors (four)

Intel Desktop Board D915GMH Technical Product Specification
16
1.3.4 Block Diagram
Figure 2 is a block diagram of the major functional areas of the board.
Intel 915G Chipset
Intel 82801FB
I/O Controller Hub
(ICH6)
Intel 82915G
Graphics and
Memory Controller
Hub (GMCH)
4 Mbit
Firmware Hub
(FWH)
System Bus
(800/533 MHz)
LGA775
Processor Socket
Parallel ATA
IDE Connector
Diskette Drive
Connector
LPC Bus
I/O
Controller
PS/2 Keyboard
PS/2 Mouse
Parallel Port
Serial Ports
Parallel ATA
IDE Interface
LPC Bus
Hardware Monitoring
and Fan Control ASIC
OM17545
Audio
Codec Retasking Jack F [Port 2]
Line Out/Retasking Jack D
CD-ROM (optional)
Retasking Jack E [Port 1]
PCI Express
x16 Interface
PCI Express
x16
Connector
= connector or socket
PCI Bus
SMBus
High Definition Audio Link
PCI Slot 1
PCI Slot 2
Mic In/Retasking Jack B
Line In/Retasking Jack C
S/PDIF (optional)
DMI Interconnect
Dual-Channel
Memory Bus
SMBus
VGA
Port Display Interface
Channel A
DIMMs (2)
Channel B
DIMMs (2)
PCI Bus
IEEE-1394a Connectors
(Optional) Serial ATA IDE
Connectors (4)
Serial ATA
IDE Interface
TPM Component
(Optional)
LPC Bus
USB Back Panel/Front Panel
USB Ports
PCI Express x1 Slot 1
LAN
Connector
Gigabit Ethernet
Controller (Optional)
PCI Express x1 Interface
LAN
Connector
10/100 LAN PLC
(Optional)
LAN Connect
Interface
Figure 2. Block Diagram

Product Description
17
1.4 Online Support
To find information about… Visit this World Wide Web site:
Intel Desktop Board D915GMH 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 D915GMH
http://developer.intel.com/design/motherbd/mh/mh_available.htm
Processor data sheets http://appzone.intel.com/literature/index.asp
ICH6 addressing http://developer.intel.com/design/chipsets/datashts
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
1.5 Processor
The board is designed to support Intel Pentium 4 processors in an LGA775 processor socket with an
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 for the D915GMH board http://www.intel.com/design/motherbd/mh/mh_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
•Failure to use a BTX power supply, or not connecting the +12 V (2x2) processor core power
supply connector to the board may result in damage to the board and/or the power supply.
•Refer to Table 4 on page 18 for a list of supported system bus frequency and memory speed
combinations.
For information about Refer to
Power supply connectors Section 2.8.2.1, page 67

Intel Desktop Board D915GMH Technical Product Specification
18
1.6 System Memory
The board has four DIMM sockets and support the following memory features:
•2.5 V (only) DDR 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 53 for information on the
total amount of addressable memory.
•Minimum total system memory: 128 MB
•Non-ECC DIMMs
•Serial Presence Detect
•DDR 400 MHz and DDR 333 MHz SDRAM DIMMs
Table 4 lists the supported system bus frequency and memory speed combinations.
Table 4. Supported System Bus Frequency and Memory Speed Combinations
To use this type of DIMM… The processor's system bus frequency must be…
DDR 400 800 MHz
DDR 333 (Note) 800 or 533 MHz
Note: When using an 800 MHz system bus frequency processor, DDR 333 memory is clocked at 320 MHz. This minimizes
system latencies to optimize system throughput.
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.

Product Description
19
Table 5 lists the supported DIMM configurations.
Table 5. 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 53 for additional
information on available memory.

Intel Desktop Board D915GMH Technical Product Specification
20
1.6.1 Memory Configurations
The Intel 82915G 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.
OM17182
Intel
R
82915P
(GMCH)
Intel
R
82801
(ICH)
Channel A
Channel B
DIMM 1
DIMM 0
DIMM 1
DIMM 0
Figure 3. Memory Channel Configuration