Use System Configuration Tool to specify runtime number of processors

For Windows Servers, it is sometimes necessary to configure the number of processors in use by the OS. Learn how and when to use the configuration tool.

Most versions of Windows Server have the System Configuration Tool, which shows a number of configuration items for the local system. I've used this utility to step-down processors on a Windows Server.

System Configuration (or msconfig.exe) has a Boot tab that allows an interactive edit of the Boot.INI file. By clicking the Advanced Options button, you edit the number of processors that are visible to the operating system on boot. In the following example, the server has one physical processor with four cores. Figure A shows the system running the System Configuration Tool. Figure A

Click the image to enlarge.

Here I can step the system down from the current inventory of visible processors (four) to any number less than that.

This is useful for one main reason: determining if lesser performance is acceptable on a system to conserve resources. In a virtualized environment, this is pretty straightforward, as you would provision processors to the virtual machine upward or downward. For physical systems, this can save unnecessary handling of the internal parts of the server and sensitive processor components. By using the System Configuration Tool, you can quickly step down to a fewer number of processors on the system via a soft configuration. The System Configuration Tool will not distinguish between sockets and cores, however; you may need to intervene to the server's BIOS to limit cores or hyperthreading.

Note: In most situations, using the System Configuration Tool to specify a limited number of processors is not an acceptable licensing workaround for per-processor situations. Consult your licensing professional for guidance on how to downsize processors for a system if necessary.

Check out a few of the System Configuration Tool's other options. While the processor limit is not very fancy, other options such as startup services and applications are available. This is a good first-line tool if the more robust Autoruns SysInternal tool is not installed on the server.

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