Analyzing Processor Activity
To determine the baseline, use the following counters to create logs of processor usage over an extended period (from several weeks to a month).
Processor\ % Processor Time
System\Processor Queue Length
Be aware of the Idle process when monitoring processor usage. The Idle process runs a thread on each processor. This thread runs when the system is not already running the thread of an active user or system process. System Monitor and Task Manager both use the Idle process to calculate time when the processor is not busy. You can see processor time for the Idle process on the Processes tab in Task Manager (called the System Idle Process) or by tracking the Process(Idle)\ % Processor Time counter in System Monitor. Notice that the Total instance for this counter includes processor time for the Idle process. To measure the Idle process, use the Process(Idle)\ % Processor Time counter, or use the Processes tab in Task Manager. Zero idle time could mean that the processor is handling a lot of work, but it could also mean that the processor or central processing unit (CPU) is overloaded.