% Interrupt Time is the percentage of elapsed time that the Processor spent handling hardware Interrupts. When a hardware device interrupts the Processor, the Interrupt Handler will execute to handle the condition, usually by signaling I/O completion and possibly issuing another pending I/O request. Some of this work may be done in a Deferred Procedure Call (see % DPC Time.) However, time spent in DPC's is not counted as time in Interrupts. Interrupts are executed in Privileged Mode, so this is a component of Processor: % Privileged Time. This counter can help determine the source of excessive time being spent in Privileged Mode.