There are two types of performance counter categories: single-instance and multi-instance. By default, a category is single-instance when it is created and becomes multi-instance when another instance is added. Categories are created when an application is set up, and instances are added at run time. In the .NET Framework version 1.0 and version 1.1, it is not necessary to know whether a performance counter category is multi-instance or single-instance. In the .NET Framework version 2.0, the PerformanceCounterCategoryType enumeration is used to indicate whether a performance counter can have multiple instances.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)