A particular occurrence of a Microsoft Windows NT Performance Monitor (System Monitor in Windows 2000) counter.
For example, if the %Privileged Time counter is being monitored for the Processor object on a symmetric multiprocessing (SMP) machine with four processors, individual instances of that counter are instances 0, 1, 2, and 3.
By using instances, you can monitor the performance of processes, threads, and devices on a per-instance basis for detailed understanding of their resource use on a machine.
Individual instances of a given counter can be displayed in the usual way using charts and graphs.