The symptoms of high CPU usage are familiar: the cursor moves jerkily and slowly, and applications begin to lag or shut down. The workstation might even begin to physically heat up as it strains to perform tasks. When diagnosing a malfunctioning system, these are signs you should start by checking the processor.
Luckily, it’s actually fairly simple to look under the hood of a Windows desktop or laptop and understand whether the workstation can be fixed, or if it’s time to replace the CPU.
What does CPU time mean?
At the core of any computing device is the Central Processing Unit (CPU), or processor, which is responsible for fulfilling the user’s instructions. A device’s CPU only has the capacity to deal with so many processes or tasks at once, and when those resources are strained, the computer’s performance begins to suffer. CPU time or processing time is measured by counting the seconds that a CPU spends processing instructions from an application or your OS. A longer count means the system is busy or overloaded.
High physical memory usage is often a consequence of using too many demanding apps, but can also be the result of a bug in a process that would normally be far less resource-intensive. Slow processing can stem from a variety of different causes, some of which will be more difficult to fix than others. But in the vast majority of cases, if you’re wondering how to lower CPU usage, the process is actually as simple as pressing Control + Shift + ESC.
How do I check CPU usage in Windows?
In order to find out what percentage of CPU a computer is using, simply open Windows Task Manager (Control + Shift + ESC) and click the Performance tab. The Processes tab offers a closer look at what might be contributing to the problem and provides a rundown of which processes are taking up the most power and RAM, which is key for figuring out how to lower CPU usage. From there, you can then either stop the processes that are using up disproportionate resources, or, if the process in question isn’t normally such a drain on CPU and memory, work to fix the underlying issues.
How do I fix high CPU usage?
If you’ve looked at the Processes tab and found that the issue can’t be attributed to uniquely demanding apps, it very well could be the result of a bug in an otherwise inconspicuous process. While any number of different issues could be plaguing your computer, let’s explore a few of the most common causes, and how to diagnose and troubleshoot high CPU usage:
- The WMI Provider Host process
The WMI Provider Host process—which typically appears as Service Host: Windows Management Instrumentation in your Processes tab—is an important part of Windows that often runs in the background. The process is used to monitor a large number of systems on a given network, and if its CPU usage is any higher than a few percentage points, that may be a sign your system is struggling with a pernicious bug.The quickest solution to this problem is the oldest one in the IT troubleshooting book: turn off the process and then turn it back on again. Use Windows Search to find Services.msc, find Windows Management Instrumentation in the window that appears, right click it, then select Restart. That should restart the service, but if you prefer, you can also simply restart your computer.If this doesn’t work, the WMI Provider host may simply be dealing with another process that is the real source of the problem. Open the Windows Event Viewer and select Applications and Service Logs, then Microsoft, then Windows, WMI-Activity, and Operational. Look for recent error entries and take down the ClientProcessID for every error you suspect is contributing to the problem. Go back to the Task Manager, click the Services tab, and sort the list by order of process ID. You can run your list of suspect processes against this list to identify the source of your malfunction.
- Too many background processes
Any computer is bound to have background processes—which are run without the user opening them in a window—taking up a percentage of CPU. But as time goes on and more applications are downloaded, those background processes can accumulate and begin to take up a nontrivial amount of resources. These processes can be stopped by unchecking them in the Startup tab, then restarting your computer, which will prevent them from being started again automatically when you turn on your device.
- A virus or an antivirus
The causes of high CPU usage are wide-ranging—and in some cases, surprising. Slower processing speeds could easily be the result of either the antivirus program you are running, or a virus that the software was designed to stop.Constantly scanning your hard drive for potential threats can take up a surprising amount of CPU power, especially if you’re using an older device or OS. If the device starts lagging at random times, it might be the result of an antivirus that’s eating into your processor load. To stop it, use your antivirus’s scheduling function to make sure it only scans your device during times that you aren’t likely to use it.Alternatively, you may have a piece of malware running on your computer that is sucking up all the processing power from your CPU, whether by running several background processes or attempting to spread itself via your email and social media. Identifying a virus on your computer isn’t easy—even scanning your device with an antivirus may not work, as many forms of malware run something called “anti-forensics” that prevents them from running if they detect security software installed on your device. Try either scanning with multiple antivirus tools or performing a manual virus removal.
A surprisingly complex issue
High CPU usage is one of the simplest issues that can impact a computer’s performance, but it can be challenging to detect the underlying cause if you don’t know where to look. If you find that high CPU usage persists—even in support of standard processes—you may simply need a faster computer. You can also reduce CPU load by adding more RAM, which allows your computer to store more application data. This reduces the frequency of internal data transfers and new memory allocations, which can give your CPU a much-needed break.
That said, even everyday users can be made aware of common CPU issues and learn to troubleshoot them, saving IT teams time and ensuring that productivity can resume as quickly as possible.
Read through our blog for other common questions and concerns related to troubleshooting: