How to Fix: Svchost.exe High CPU Usage

Dennis Faas's picture

How to Fix: Svchost.exe High CPU Usage

Infopackets Reader Ben J. writes:

" Dear Dennis,

I just reinstalled Windows 7 on my machine, and from the get-go the machine is very slow to use. I ran Windows Task Manager to see what is going on, and the svchost.exe process is consuming 50% of my CPU. I have disabled the sleep mode on my computer and let svchost run for a few days, but nothing has come of it - it's still causing high CPU usage. I should also mention that I have not yet received any Windows Updates on my computer for the last week. What is causing the svchost process to run at high CPU usage? How can I get my Windows Updates downloaded? "

My response:

The svchost.exe process stands for "service host" and often refers to more than one Windows Service that runs in the background. For example, one svchost process may contain: Remote Desktop Services, Storage Service, Network Connection Broker, Data Sharing Service, and many more. That said, it would not be uncommon to have up to 15 or more svchost.exe processes running on the machine, which each process referencing multiple Windows Services. All these services combined effectively run Windows from 'behind the scenes', so to speak.

You can use Windows Task Manager to help determine which Windows Services are associated with a particular svchost.exe process. However, when it comes to troubleshooting processes, Process Explorer is a better choice, because it has much more detail. Below I'll explain two approaches you can use when it comes to researching Windows processes.

How to Determine Which Services are Associated with Svchost.exe: Using Task Manager

You can use Windows Task Manager to determine which tasks are associated with a svchost.exe process. To do so:

  1. Right click on the Task Bar, then select "Task Manager".
  2. The Task Manager window will appear. In Windows 8 and 10: if you see an option for "More details" near the bottom left of Task Manager, click it so that the window is fully expanded. Next, go to the Details tab, then click the CPU column to sort processes by usage (descending). In Windows XP, Vista, and 7: click the Processes tab, then click the CPU column to sort processes by usage (descending).
  3. The svchost.exe task that is consuming high CPU usage should automatically float to the top of the list. Left click the svchost.exe process to highlight / select it, then click the Processes column heading to stop sorting the list by CPU usage - and to stop the task you just selected from constantly moving around in the list.
  4. Next, scroll through the list of tasks in the Processes column, until you see the blue highlighted svchost.exe process. Following that, right click over top of the svchost.exe, and select "Go to service(s)".
  5. The Task Manager window will now change to the 'Services' tab, and will show at least one Windows Service task already highlighted. If there are more Windows Services associated with the svchost.exe, they will also be highlighted.

This gives you a general idea as to which service(s) are related to a specific task when it comes to svchost.exe; however, it does not tell you exactly which Windows Service is causing the high CPU load. In that case, you will need to use another utility, called Process Explorer - described next.

How to Determine Which Service is Causing High CPU Load: Using Process Explorer

When it comes to process specifics, Process Explorer will tell you just about everything you need to know about a task or service - right down to its associated CPU usage and description. Here's how you can use Process Explorer to determine exactly which Windows Service is causing you grief when it comes to svchost.exe:

  1. First: download and install Process Explorer.
  2. Once the main Process Explorer window appears, click the CPU column to sort processes by CPU usage.
  3. The processes with the highest CPU load will float to the top of the list. Left click the svchost.exe process to highlight it; the row will turn dark blue. Following that, click the Process column (heading) to stop sorting tasks by CPU usage - and to stop the task you just selected from constantly moving around in the list.
  4. Next, scroll through the list until you see the svchost.exe task you clicked on earlier - it will be highlighted in dark blue. Now, look at the indented tasks below the svchost.exe process, and it will tell you the task .exe filename (program), the description of the task, and the CPU load associated with the task. Look for the task which is causing high CPU load.

Now that you know what task is causing the issue, you can now research the problem online Google. For example, if the Windows Update Service is causing high CPU load, then you might want to search for "windows update high cpu load", or such.

What to Do if the Windows Update Service is Causing High CPU Usage

For the record, it is not uncommon for svchost.exe to run at 100%, 50%, or 25% CPU load for hours at a time as this host process usually refers to the Windows Update service. If that is the case you should let the process run for as long as it needs to in order to complete the task. This is particularly true when it comes to Windows 7, as there are literally hundreds of updates to download after Windows is freshly installed.

As such: if you have let the svchost.exe process (associated with Windows Update) run for anywhere between 2 to 4 hours and nothing has changed, then you may have a broken Windows Update Service. This is a very common and perplexing issue, even after a fresh install of Windows. In that case I suggest you refer to my Windows Update Won't Update article for a possible solution; if you are really stuck with this issue you can contact me for additional support.

Additional 1-on-1 Help: From Dennis

If all of this is over your head, or if you need help troubleshooting a task, then I can help using my remote desktop support service. Simply send me an email briefly detailing your problem, and I will get back to you as soon as possible.

Got a Computer Question or Problem? Ask Dennis!

I need more computer questions. If you have a computer question - or even a computer problem that needs fixing - please email me with your question so that I can write more articles like this one. I can't promise I'll respond to all the messages I receive (depending on the volume), but I'll do my best.

About the author: Dennis Faas is the owner and operator of With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.

Rate this article: 
Average: 3.9 (9 votes)


dan_2160's picture

I don't want to direct any business away from Dennis, but readers should be aware that the freeware program "Windows Repair All in One" can fix a corrupt Windows update service. At least it did for me.

The key with this program is to follow the instructions to the letter. You get the opportunity to specify exactly which problems you want to fix, including a corrupted Windows Update Service. Somehow my Windows 10 Pro computer had stopped downloading and installing updates. Windows Repair All in One fixed the problem on the first try.

After running Windows Repair (All in One), check the following which sometimes get changed back to default settings: you may have to reset your default programs and file associations. Also check your System Restore settings. You install new versions of Windows Repair right over the old version - no need to uninstall the old version.

I hope this helps. But remember, follow the instructions exactly.

tlowes_6847's picture

My two cents: I have reinstalled Windows 7 several times for myself and for friends, it takes longer and longer as time goes by to do windows update after a clean install. Last time I did this it took over twelve (12) hours to run and downloaded over 200 updates. It's unfortunate that Microsoft does not have a package to do this with, all updates must be done one at a time, weather you do it on line or offline. Offline has some restriction as some updates need other updates to be installed first.

jamies's picture

Re identifying what's happening

1) Task Manager - turn on all the columns for the details ( processes) so you can see what file ( or actual command) initiated the process
The memory and pagefile Delta's are useful for type of activity as are the bytes read and written. also turn on performance monitor ( from the performance tab) and that will show more detail on what is happening within the system.

Remember these monitors use memory - and Microsoft Update seems to need about 1GB of memory or it will cause massive amounts of pagefaults and fail to install lots of fixes.
You will also find that anti-virus - real-time checking uses lots of resources - it will be checking the files that the Microsoft Update reads - so that's all the files on the OS partition read again - or maybe twice more.
Another thing - set the pagefile to be a minimum of 1.5 times the actual memory, and at least 4000MB and not expandable (system managed) - expanding and contracting the pagefile also uses large amounts of resources lots of MFT and MBT table processing for each small increment and release of each of those previously acquired increment.

So -

I've just reinstalled Win7 (32 bit) Ultimate onto an older system ( 2Ghz dual core 2GB memory & 160GB drive)
I started from an older instance of windows - so that was SP1 to apply first -
Highlights -
After getting the update that would install the SP1 update, and 76 fixes including WGA ( to verify I had a licence)
Windows Update Another SP pack
Windows Update Net 4 and other bits
Manually downloaded and installed IE11 * Security Essentials

Windows Update is not fast, but do not make the mistake of going for Microsoft Update in the expectation that will be better.

After I opted for the 'better option' First couple of pass of Microsoft Update took over 5 hours to scan the base OS appearing to take a couple of hours to read all the files on the OS partition (slowly), then cogitate for another 4 hours or so, before reporting over 200 fixes needed.
several hours later - it needed rerunning for the failed to install fixes (over 100 failures from the 250 Needed and Optional, and then a similar slow process for those 100, and a few more)
Another 100+ fixes after that - in all, maybe over 1.5GB downloaded slowly from the MS site -

BUT cheer up - Once the Microsoft update has finished processing your entire OS partition - and I presume, from whet I have noted - written away details of what it found, which it only does if all selected fixes apply without error.

(Note to self - next time try just applying 1 fix from the first list Microsoft Update presents, and remember to start the scan early in the morning to avoid late working!)

And while there seems to be lots apparently un-needed, and certainly slow processing of the installed files, there is also, apparently, a lot of the delay at the MS site! - guess that's why Win-10 users get to take the fixes from their friends and others.

wysetech2000_6856's picture

I have had the same problem after installation of Windows 7 and was slightly involved with Microsoft on a fix for the problem. You will need to download Update Service Agent 7.6, Windows Update KB3083710 and KB3012810 from Microsoft update downloads. Install them. Make sure the background intelligent service is set to "started" under the services menu and your problems should be solved.

jamies's picture


Thanks for that -
Added to my list of actions to do when re-setting-up a Win-7 system.

I'll also check to see if those fixes were downloaded and installed in one of the slow sessions.

Don't expect any response soon - I've (I hope) finished with the XP and W7 system resetup's - well for a month at least.