`NotCPUCores` isn[SQ]t a standard Windows system variable or environment variable. There[SQ]s no built-in Windows functionality or common application that uses a variable with that exact name.

It[SQ]s possible that :

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It[SQ]s a custom variable:

A specific application or script might define `NotCPUCores` for its own internal use. Its meaning would be entirely dependent on that application[SQ]s code.
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It[SQ]s a typo:

Perhaps the intended variable name is slightly different. If you encountered this in a log file or script, double-check the spelling. Something like `NumberOfCores`, `LogicalProcessors`, or `CPUCount` might be closer to what you[SQ]re looking for, depending on the context.
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It[SQ]s related to a third-party tool:

Some performance monitoring or system management tools might use a variable with a similar name to represent the number of *inactive* or *unavailable* CPU cores. If this was encountered within the context of such a tool[SQ]s documentation or output, check that tool[SQ]s specific documentation.

To find out what `NotCPUCores` means, you need to determine the context where you encountered it. Providing more information about where you saw this variable (e.g., a screenshot, the name of the application or script) will allow for a more precise answer.