What are the Most Common Causes of High CPU Usage?

N. Madison

There are many things that may lead to high computer processing unit (CPU) usage. One of the most common is having too many applications open and in use at one time. Malware, which is malicious software such as spyware, may lead to high CPU usage as well. Sometimes the problem is software that fails to function exactly as it should. Once an individual identifies the problem, he may fix high CPU usage by closing programs; removing malware or software that's at fault; or seeking help from a computer repair person.

High CPU usage often occurs when people use their computers to multitask.
High CPU usage often occurs when people use their computers to multitask.

One of the most common causes of high CPU usage is the use of too many computer applications at one time. This often occurs when an individual is multitasking on his computer. For example, a user may choose to surf the Internet, listen to music, and run a scan for viruses at the same time. Sometimes a person will even attempt to perform word processing tasks while running these other applications and have background programs enabled to check for updates to software. While a computer user may be able to accomplish all of these things at once, having so many applications running can lead to high CPU usage.

A Central Processing Unit (CPU).
A Central Processing Unit (CPU).

In some cases, harmful computer software, referred to as malware, is at fault for high CPU usage. Malware can include viruses; spyware, which collects information from a person's computer; and adware, which shows the computer user advertisements. These programs are often at fault when a person is dealing with frequent pop-up ads or notices that his browser is directed to a page he hasn’t selected.

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Viruses, spyware, and other malware can be a cause of high CPU usage.
Viruses, spyware, and other malware can be a cause of high CPU usage.

High CPU usage may also result from programs that start to malfunction. For example, a word processing program may work perfectly for a period of time and then suddenly start to freeze periodically. Sometimes a malfunctioning program will attempt to use a significant portion of a system's resources in order to run. Often, a program that is incompatible with a person’s operating system contributes to high CPU usage as well.

It is usually considered normal for CPU usage to be high from time to time. If CPU usage is high most or all of the time, however, this may be a sign of a problem. In such a case, a person may try closing some of applications he is using or stopping some of the programs that are running in the background. He may also try getting rid adware and malware; using an online tutorial to find other fixes for high CPU usage; or contacting a computer professional for help.


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Discussion Comments


If you do find that virus scanners, regular systems files are bogging down your computer and you have an older system, it might be time to think about getting a new one that can better handle the demanding chores of modern operating systems.

Either that or consider going to a less resource intensive operating system such as Linux. As a bonus, you really don't need to fret over virus protection too much on those systems.


@Logicfest -- I don't know that I would mess around too much with that virus scanner. Most people pick up a virus by poking around on the Internet and opening emails. You really want virus shields taking a hard look at programs coming into your system. Otherwise, what's the point?


It is a supreme irony that one of the the things that can cause high CPU usage is a hyperactive virus scanner. If it is updating virus definitions, CPU usage might be high. If it is actively scanning your system, CPU usage might be high. Some of them are set to scan every single file that enters your system, which can make surfing the Internet a trudging experience on older, slower systems.

The same goes for spyware and adware scanners.

Some advice? Do some research and find out if your virus scanner really needs to check every single file on your system. Do you really need an active spyware scanner or is it OK to open one and scan your system once a week or so? If you can do a scan just every now and again, that could cut down on high CPU usage.

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