Desktop Boards
Desktop Boards
Single and multi-channel memory modes

Several types of memory modes can be configured on Intel® Desktop Boards, depending on how many memory modules (DIMMs) are installed:


Single-channel (asymmetric) mode
This mode provides single-channel bandwidth operations and is used when only one DIMM is installed or when the memory capacities of more than one DIMM are unequal. When using different speed DIMMs between channels, the slowest memory timing is also used.

Single-channel with one DIMM

Single-channel with three DIMMs

At boot, the memory configuration is detected and you might see this alert message:

Alert: Maximum memory performance is achieved with equal amounts of memory installed in each channel. Press any key to continue.

With the DIMMs that are currently installed, the computer is set to single-channel mode, but it can be set to dual-channel mode. If you shut down and rearrange the DIMMs properly, you can establish dual-channel mode.

Dual-channel (interleaved) mode
This mode offers higher memory throughput and is enabled when the memory capacities of both DIMM channels are equal. When using different speed DIMMs, the slowest memory timing is used.

Dual-channel with two DIMMs

Dual-channel with three DIMMs

Dual-channel with four DIMMs

Rules to enable dual-channel mode
To achieve dual-channel mode, the following conditions must be met:

  • Same memory size. Examples: 1 GB, 2 GB, 4 GB.
  • Matched DIMM configuration in each channel
  • Matched in symmetrical memory slots

Configurations that do not match the above conditions revert to single-channel mode. The following conditions do not need to be met:

  • Same brand
  • Same timing specifications
  • Same speed (MHz)

The slowest DIMM module populated in the system decides memory channel speed.

Triple-channel mode
Triple-channel interleaving reduces overall memory latency by accessing the DIMM memory sequentially. Data is spread through the memory modules in an alternating pattern.

Three independent memory channels give two possible modes of interleaving:

  • Triple-channel mode is enabled when identical matched memory modules are installed in each of the three blue memory slots.
  • If only two of the blue memory slots are populated with matched DIMMs, dual-channel mode is enabled.

Quad-channel mode
This mode is enabled when four (or a multiple of four) DIMMs are identical in capacity and speed, and are put in quad-channel slots. When two memory modules are installed, the system operates in dual-channel mode. When three memory modules are installed, the system operates in triple-channel mode.

Quad-channel with four DIMMs:

Quad-channel with eight DIMMs:

Flex mode
This mode results in both dual and single-channel operation across the whole of DRAM memory. The figure shows a flex mode configuration using two DIMMs. The operation is as follows:

  • The 2 GB DIMM in slot 1 and the lower 2 GB of the DIMM in slot 2 operate together in dual-channel mode.
  • The remaining (upper) 2 GB of the DIMM in slot 2 operates in single-channel mode.

Related Topics:
System memory information for your board
Troubleshooting system memory issues
Multi-channel memory architecture

This applies to:

Intel® Desktop Board D2500CC
Intel® Desktop Board D2500HN
Intel® Desktop Board D2550DC2
Intel® Desktop Board D2550MUD2
Intel® Desktop Board D2700DC
Intel® Desktop Board D2700MUD
Intel® Desktop Board D410PT
Intel® Desktop Board D425KT
Intel® Desktop Board D510MO
Intel® Desktop Board D525MW
Intel® Desktop Board DB65AL
Intel® Desktop Board DB75EN
Intel® Desktop Board DB85FL
Intel® Desktop Board DH55HC
Intel® Desktop Board DH55PJ
Intel® Desktop Board DH55TC
Intel® Desktop Board DH57DD
Intel® Desktop Board DH57JG
Intel® Desktop Board DH61AG
Intel® Desktop Board DH61AGL
Intel® Desktop Board DH61BE
Intel® Desktop Board DH61BF
Intel® Desktop Board DH61CR
Intel® Desktop Board DH61DL
Intel® Desktop Board DH61HO
Intel® Desktop Board DH61KVCH
Intel® Desktop Board DH61SA
Intel® Desktop Board DH61SKCH
Intel® Desktop Board DH61WW
Intel® Desktop Board DH61ZE
Intel® Desktop Board DH67BL
Intel® Desktop Board DH67CF
Intel® Desktop Board DH67CL
Intel® Desktop Board DH67GD
Intel® Desktop Board DH67VR
Intel® Desktop Board DH77DF
Intel® Desktop Board DH77EB
Intel® Desktop Board DH77KC
Intel® Desktop Board DH87MC
Intel® Desktop Board DH87RL
Intel® Desktop Board DN2800MT
Intel® Desktop Board DP55KG
Intel® Desktop Board DP55SB
Intel® Desktop Board DP55WB
Intel® Desktop Board DP55WG
Intel® Desktop Board DP67BA
Intel® Desktop Board DP67BG
Intel® Desktop Board DP67DE
Intel® Desktop Board DQ57TM
Intel® Desktop Board DQ57TML
Intel® Desktop Board DQ67EP
Intel® Desktop Board DQ67OW
Intel® Desktop Board DQ67SW
Intel® Desktop Board DQ77CP
Intel® Desktop Board DQ77KB
Intel® Desktop Board DQ77MK
Intel® Desktop Board DQ87PG
Intel® Desktop Board DX58OG
Intel® Desktop Board DX58SO
Intel® Desktop Board DX58SO2
Intel® Desktop Board DX79SI
Intel® Desktop Board DX79SR
Intel® Desktop Board DX79TO
Intel® Desktop Board DZ68AF
Intel® Desktop Board DZ68BC
Intel® Desktop Board DZ68DB
Intel® Desktop Board DZ68PL
Intel® Desktop Board DZ68ZV
Intel® Desktop Board DZ75ML-45K
Intel® Desktop Board DZ77BH-55K
Intel® Desktop Board DZ77GA-70K
Intel® Desktop Board DZ77RE-75K
Intel® Desktop Board DZ77SL-50K
Intel® Desktop Board DZ87KLT-75K

Solution ID: CS-011965
Last Modified: 22-Nov-2013
Date Created: 26-May-2004
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