Definition of CPU Usage

By Cameron Easey

CPU usage is a term used to describe how much the processor is working. A computer's CPU usage can vary depending on the types of tasks that are being performed by the processor. CPU usage can be monitored to see how much of the processor's capacity is in use. Excessive CPU usage for certain programs can be a cause for concern.


The CPU usage of a system can be monitored in many ways by using various software programs. One way to monitor CPU usage is to use the Windows Task Manager. The Task Manager has a Performance tab that displays a graph of CPU usage. Another way to monitor CPU usage is to use a third party program such as CacheMan (see Resources).


The percentage of CPU usage indicates how much of the processor's capacity is currently in use by the system. When the CPU usage reaches 100% there is no more spare capacity to use for running other programs. When the percentage of CPU usage begins to max out at 100% additional action may need to be taken.


Abnormally high CPU usage by particular programs can be an indication that there is something wrong with the computer system. Programs such as an Internet browser that start to have heavy CPU usage may be an indication of spyware or a script running on a web page. Some type of spyware can use an Internet browser to transfer information. Also, an extensive use of JavaScript on a web page can cause high CPU usage.


Certain types of programs can use large amounts of CPU processing power. Some programs can perform tasks such as anti-virus and anti-spyware scanning. Excessive processor usage is normal for these programs and is not a cause for concern.

Reducing Usage

CPU usage can sometimes be reduced if it is constantly working at or near 100% for an extended period of time. One way to reduce CPU usage is to terminate or close other applications that are currently running. Changing an application's priority status can also reduce the amount of processor usage that is needed. Priority status can be changed in the Process tab located in the Windows Task Manager.