CPU Usage

• When viewing the list of processes, higher values in the CPU column mean the corresponding processes are using more of the CPU's computational power. The numbers represent the percentage of available CPU power in use by the processes.
  
  

System Idle Process

• Unlike other processes, the System Idle process instead lists the percentage of CPU power that remains available for use, or the percentage currently idling. This number will often reach well over 90 percent when the system is performing no other tasks.
  
  

Performance

• A higher percentage in the System Idle's CPU column means that the computer is performing well, and that much of the system's resources are still available for additional tasks. The System Idle process does not itself hinder the the system's performance.
  
  

Percentages

• Adding the percentages of running processes to the System Idle's percentage returns a result of 100. Referencing the System Idle usage gives users a quick way to estimate how much CPU is in use without examining other individual processes.