You have arrived here because you have identified a high amount (greater than 50%) of processor time (\Processor(*)\% Processor Time), a high amount (greater than 30%) of privileged time (kernel time) (\Processor(*)\% Privileged Time) and a high amount of deferred procedure calls (greater than 20%) (\Processor(*)\% DPC Time) or a high number of interrupts (greater than 20%) (\Processor(*)\% Interrupt Time) on your Windows computer. If this is not correct, then return to the Start of the Performance Guide.
% DPC Time is the percentage of time that the processor spent receiving and servicing deferred procedure calls (DPCs) during the sample interval. DPCs are interrupts that run at a lower priority than standard interrupts. % DPC Time is a component of % Privileged Time because DPCs are executed in privileged mode. They are counted separately and are not a component of the interrupt counters.
High Deferred Procedure Calls (DPCs) and high interrupts are typically caused by very busy or poorly written device drivers. Consider using a tool such as Microsoft xPerf to assist with diagnosis of this problem.
Here is an article by Windows IT Pro Magazine that goes into diagnosing DPC issues using Microsoft xPerf:
Windows IT Pro Magazine: Examining xPerf http://www.windowsitpro.com/print/performance/examining-xperf.aspx
Tip: If the computer hangs often, then while it is hung, press the Cap Lock key on the keyboard to see if the light on the keyboard toggles on and off when you press it. If the Cap Lock key light does not respond, then the computer is hung due to a hardware problem. Otherwise, it is most likely a software problem.