High CPU usage can be a symptom of a number of PC conditions, such as insufficient or bad memory, viruses or malware producing a lot of background activity, insufficient hardware capacity to run all the software you are trying to run simultaneously, or a highly fragmented or corrupt Windows registry. Whatever the reason, high CPU usage is usually a strong indication that there is something seriously wrong that requires immediate attention.

Symptoms of high CPU usage

When CPU usage on a PC is getting close to 100%, there are normally many symptoms telling the user there is a problem. The PC will usually slow down considerably and may completely freeze for brief or even extended periods of time. The processor may start to overheat. Applications or the operating system itself may end up crashing and a reboot may be required.

Causes of high CPU usage

If CPU usage on a PC is getting close to 100%, it is an indication that there is something going on in the background that is consuming too much processing power. The background activity may be produced by a virus or malware, by hardware specs being too low for the resource-heavy software the user is trying to run, as well as by Windows registry having too many invalid entries and broken shortcuts. Such entries cause the system to produce too much activity if, for instance, an application or component is not found at the location pointed to by a registry key, or if a key is corrupt and cannot be processed correctly.