Desktop Boards

Single/Dual Channel Memory Modes

The memory configuration information in this document applies to the Intel® Desktop Boards listed below.

Dual Channel memory configurations will provide increased performance over Single Channel configurations. Follow the guidelines below when configuring your system memory to provide the best possible performance for your system.

Memory Configuration for Dual Channel Mode

Two or Four DIMMs - Populated Symmetrically

You will get Dual Channel Mode if you populate the memory slots with two or four identical symmetrical DIMMs, such as in these examples:

Three DIMMs - Populated Symmetrically

You will get Dual Channel Mode if you populate the memory slots with three DIMMs, such as in this example:

For three-DIMM dual channel mode, the DIMMs in Channel A must match and the DIMM in Channel B (either slot) must be equal in capacity to all of Channel A.  While probably not common, this scenario is likely if you upgrade the memory on your system.

Rules to Enable Dual Channel Mode
To achieve Dual Channel mode, the following conditions must be met:

• Matched DIMM configuration in each channel
• Same Density (128MB, 256MB, 512MB, etc.)
• Same DRAM technology (128Mb, 256Mb, or 512Mb)
• Same DRAM bus width (x8 or x16)
• All either single-sided or dual-sided
• Matched in both Channel A and Channel B memory channels
• Populate symmetrical memory slots (Slot 0 or Slot 1)

Note: Configurations that do not match the above conditions will revert to Single Channel mode.

The following conditions do not need to be met:

• Same brand
• Same timing specifications
• Same DDR speed

Note: Memory channel speed is determined by the slowest DIMM module populated in the system.

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Memory Configuration for Single Channel Mode

You will get Single Channel Mode if you populate memory modules only into single channels, such as in these examples:

You will get Single Channel Mode if you populate memory modules non-symmetrically, such as in these examples:

You will get Single Channel Mode if you populate with non-identical DIMMs, such as in these examples:

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

Maximum memory performance is achieved with equal amounts of memory installed in each channel.
Press Any Key To Continue...

This means that with the DIMMs that are currently installed, the computer is set to single channel mode but, in fact, is capable of dual channel mode.  If you shut down and rearrange the DIMMs properly, you'll achieve dual channel mode.

Note: Memory channel speed is determined by the slowest DIMM module populated in the system.

BIOS Settings
The BIOS setup Main screen will display Memory Mode information, as follows:

This applies to: