Svchost.exe is known to cause high CPU usage problems. I’m sure you’ve been in a situation like this: you’re working on your computer and enjoying yourself when all of a sudden it becomes agonizingly slow and even starts freezing up. You press CTRL+ALT+DEL to open the Task Manager, click on the Processes tab,  and see that there are several instances of svchost.exe running and one of them is using up 90% – 100% of CPU! Some people will think: “Oh no! My computer’s got a virus!!!”. Well, that might be true, because some malware pretends to be svchost, but most likely it’s just Windows being Windows.

So, what does svchost.exe do and why is it there in the first place? Svchost is there to host services and run DLLs. You might have noticed that most programs have their own .exe files and can run on their own. DLLs are different – they can’t launch themselves. That’s why svchost.exe exists – it launches and runs DLLs. You can check out the FileInspect Process Library to find out more about the svchost.exe process.

Now the question is how to stop svchost.exe from stealing CPU usage. First of all, you’ll need to find out which of the svchost.exe instances is the culprit and is causing your computer to slow down. Also you need to identify the actual application running it.

In this respect Vista users are luckier than XP users – Vista built-in Task Manager has a Go to Service(s) option, that allows you to see all services running under a selected process. To view that, right-click on the svchost.exe process you want to inspect and choose Go to Service(s).

You will be redirected to the Services tab where you’ll be able to see the services running under that particular svchost.exe process.

To do the same thing Windows XP users will have to download a free Microsoft (originally Sysinternals) tool called Process Explorer, that gives you detailed information for each running process. All you need to do is download it and click the .exe file – no installation is required.

Once you’ve got it running, hover the mouse point over each svchost.exe process and a tooltip windows with all the information needed will appear.

How to Fix It?

First of all, if the process that is eating up CPU is not a Windows process and is called scvhost instead of svchost, kill it, scan your computer for viruses, and uninstall the program that runs the process. Note that if your computer is infected, the virus might not let you uninstall it that easily – the application  might not even show up in the Add/Remove Programs window. A simple and reliable way to get rid of malware applications is to use a software uninstaller. These utilities find all entries related to the application you are trying to uninstall and remove the completely. If svchost was a virus that you removed, but you are still getting the errors, there might be some bits of malware left in the Registry. A good program to help you uninstall software and clean the Registry is Auslogics BoostSpeed. It contains both an uninstaller and a Registry cleaner, plus lots of other useful utilities to optimize and protect your computer.

However, most likely svchost.exe with high CPU usage will be a Windows process, such as Task Scheduler, firewall, or Microsoft Update. Sometimes simply restarting your computer gets rid of the problem. If not, try downloading the most recent Windows Updates. If for some reason you can’t, go to the Control Panel – Administrative Tools – double-click the Services shortcut (or click Start – Run - type in services.msc – hit Enter), find the required service, right-click on it, go to Properties and select Disabled from the Startup type box. You can always re-enable it later, so don’t worry. Reboot your computer and then go to the Microsoft website and download updates. Install them, re-enable the service that you have stopped, and restart again. Hopefully everything will be working now.

Another way to get rid of svchost.exe high CPU usage problem is to open the Task Manager (CTRL+ALT+DEL), find the process that is causing the problem, right-click on it, go to Set Priority and set it to Below Normal (or Idle if Below Normal doesn’t help). Keep in mind that setting it to Idle might interfere with your networking services, especially if you’re at work and part of a large network.

If you want to improve overall computer performance, you can disable services that you never use. Not using them doesn’t mean that they don’t take up system resources. You can disable services by going to the Control Panel – Administrative Tools and double-clicking the Services shortcut. The only problem is that you can do more harm than good if you don’t know exactly what you are doing. Of course, there are various guides published on the Internet and some of them are really good, but you must remember that the results may be different for different computers. That’s why it’s a lot safer to use a program like Auslogics Service Manager. It checks your computer for unnecessary services, taking into account all the applications you have installed, and recommends which ones are safe to disable and which are not.

You can disable services straight from the program window and re-enable them whenever you need them running.