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Boot Parameters to Manipulate Memory

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You can simulate a low-memory environment for testing without changing the amount of physical memory on the computer. Instead, you can limit the memory available to the operating system by using truncatememory or removememory options with the BCDedit /set command.

The truncatememory or removememory options are available in Windows 7 and later.

  • The truncatememory option disregards all memory at or above the specified physical address.

  • The removememory option reduces memory available to Windows by the specified amount (measured in MB). Both options reduce memory, but the removememory option is better at restricting the operating system to use the specified memory while accounting for memory gaps. Because of this, the use of removememory is recommended.

Boot Parameters to Simulate a Low Memory Environment in Windows

To simulate a low memory environment, use the BCDedit /set command and the removememory option to modify a boot entry. Set the value of removememory to the amount of physical memory on the system minus the desired memory size for this test.

For example, to limit the memory of a computer with 2 GB of physical memory to a maximum of 512 MB of available memory, set the value of the removememory parameter to 1536 (2 GB (2048 MB) - 512 MB = 1536 MB).

The following example shows a BCDEdit command used to remove 1536 MB of memory from the total available to the system for the specified boot entry.

In this example bcdedit /enum was used to determine the BCD data store GUID is {18b123cd-2bf6-11db-bfae-00e018e2b8db}. For information on specifying a specific boot entry, or working with the default boot entry, see Editing Boot Options.

bcdedit /set {18b123cd-2bf6-11db-bfae-00e018e2b8db} removememory 1536

You can also use the truncatememory option with the bcdedit /set command to achieve the same result. When you use this option, Windows ignores all memory at or above the specified physical address. Specify the address in bytes. For example, the following command sets the physical address limit at 1 GB for the specified boot entry. You can specify the address in decimal (1073741824) or hexadecimal (0x40000000).

bcdedit /set {18b123cd-2bf6-11db-bfae-00e018e2b8db} truncatememory 0x40000000

After rebooting, use a utility such as systeminfo to confirm the the amount of available memory.

When you are finished testing, you can remove the removememory and truncatememory boot entry options using the BCDEdit /deletevalue command.