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CPU Usage always at 70%+ until task manager is open


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Hi Team,

My CPU usage is always at 90% or 100%. But when I open task manager, after a couple of seconds it drops to 30-50%. Suspecting malwares, I started a new topic here (link below) but after several steps/fixes, there were no malwares identified in the system. The staff recommended me to create my own topic in this forum to see if its Windows related. 


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It sounds like it is most likely some kind of idle task and/or conditional scheduled task executing in the background and when you launch Task Manager (or likely any other new active/primary process) the background task subsides until the system is in an idle state again.  When this occurs, are you seeing any network/bandwidth usage by any chance?  The reason I ask is because it is possible that it is something like Windows Update running in the background when the system isn't active.  Another possibility would be something like the built in search indexer or an antivirus if you're using a third party AV that perhaps performs a background scan whenever the system is idle (Kaspersky has a function like this and I believe a few other AVs do as well).

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As part of the previous post, I was asked to uninstall Kaspersky which I did. But the behavior is still the same. No, there is no spike in network/bandwidth usage when the CPU is at 100%. Please note that that the "system is not idle". Even when I have a few simple applications open like (word, excel, etc.) it shoots up to 100%.

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Please do the following so that we may take a closer look:

  1. Download and run the Malwarebytes Support Tool
  2. Accept the EULA and click Advanced tab on the left (not Start Repair)
  3. Click the Gather Logs button, and once it completes, attach the zip file it creates on your desktop to your next reply

Create an Autoruns Log:

Please download Sysinternals Autoruns from here and save it to your desktop.

Note: If using Windows VistaWindows 7Windows 8/8.1 or Windows 10 then you also need to do the following:

Right-click on Autoruns.exe and select Properties
Click on the Compatibility tab
Under Privilege Level check the box next to Run this program as an administrator
Click on Apply then click OK

  • Double-click Autoruns.exe to run it.
  • Once it starts, please press the Esc key on your keyboard.
  • Now that scanning is stopped, click on the Options button at the top of the program and verify that the following are checked, if they are unchecked, check them:

Hide empty locations
Hide Windows entries

  • Click on the Options button at the top of the program and select Scan Options... then in the Autoruns Scan Options dialog enable/check the following two options:

Verify code signatures
Check VirusTotal.com

  • Once that's done click the Rescan button at the bottom of the Autoruns Scan Options dialog and this will start the scan again, this time let it finish.
  • When it's finished and says Ready. on the lower left of the program window, please click on the File button at the top of the program and select Save and save the file to your desktop and close Autoruns.
  • Right click on the file on your desktop that you just saved and hover your mouse over Send To and select Compressed (zipped) Folder
  • Attach the ZIP folder you just created to your next reply


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Thanks.  You appear to have quite a lot of programs configured to run in the background on your system, and it is likely one of those that is causing the spikes in CPU/resource usage.  We'll start by cleaning some things up and disabling some things that you likely don't really need to have running in the background all the time.

First, I noticed that you have Malwarebytes scheduled to scan your system every hour.  This is definitely excessive and a major waste of resources.  I would suggest changing your schedule to once per day or even once per week, as the real-time protection in Malwarebytes should prevent most if not all threats that a scheduled scan might detect anyway.

Next, I would recommend disabling all of the background monitoring and automatic cleaning functions in CCleaner.  Generally cleaning out temp files, browser caches and all the other stuff that CCleaner and tools like it remove can be good for privacy and system performance, however having a tool like that constantly running in the background and monitoring and cleaning all the time will hinder system performance much more than allowing temp files to build up over time and cleaning them manually on a regular basis would so I would instead recommend disabling CCleaner from running in the background and simply using it once a day or once a week to clear out all your temp files etc.  Instructions on how to disable it can be found here.

You mentioned that you removed Kaspersky, however I still see several active Kaspersky components on the system.  Did you reinstall it?  If not, then you should probably try and eliminate the remaining components.  I would recommend using their removal tool which can be found here.

So that's a start, and while there are still a lot of items running at startup/in the background on your system, I don't want to do too much yet as I see you've already apparently done this using MSConfig and I don't want to damage anything by messing with your system too much (and just for future reference, using MSConfig as a startup manager is generally a bad idea as it is intended more as a diagnostic tool than anything; a dedicated tool like Autoruns is much better suited to this task, though caution should be taken no matter what is being used as disabling the wrong thing with any tool could cause major problems with a system).

Please let me know how things are running after doing the above and let me know if you are still encountering the high CPU usage issue or not.


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If I might intrude here.

I believe that there is nothing using 100% CPU - this is simply the way that Task Manager works nowadays.
(Although it may be an unintentional bug that Microsoft has introduced in it).

When you launch Task Manager it will always start by showing 100% CPU usage - until it can monitor just what is actually being used, which only takes a second or so.
This ties in with what the OP is reporting.
Nothing is actually using 100% CPU, it's just a number that is being shown while it works out what your CPU usage is.

I can repeat this constantly here with my Winindows 10 1903-
Open Task Manager and it shows 100% CPU for the first second or two, then drop down to the actual level in use.
Close (not minimise) and relaunch Task Manager and it will again show 100% CPU and then drop down to the actual level in use.
And again, and again, for as long as you want to keep closing and relaunching it, it will always show 100% CPU when it is launched.

I managed to catch a screenshot and you can see that although its showing 100% at the top all the figures in that column show 0% because it hasn't worked them out yet.


I believe that it used to show 0% CPU at the top until it monitored what is actually in use, the same as Disk and Network show 0% at TM launch.

Why Microsoft have changed it I have no idea, like I say it may be unintentional?

PS. I noticed something similar happening with this months Patch Tuesday updates.
If you watched them they started off showing 100% downloaded and then (after a while) dropped to the real figure, the same happened with 'installing' starting at 100% and then dropping to what had actually been installed.

Edited by nukecad
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It could just be the spike from launching Task Manager itself, as that will hit the CPU initially as Task Manager's executable is launched into memory.

That said, I still think there very likely is something causing background CPU spiking/resource usage on the OP's system, especially after looking at the Autoruns file that was provided.  There are a lot of background processes, monitors and other tasks running in the background that very likely are eating available resources during normal operation.  This is why I prefer to do my performance tuning/tweaking/cleaning/maintenance tasks manually on my own schedule rather than having programs constantly running in the background to manage it for me, because every added task that runs in the background constantly will consume that much more memory and that many more CPU cycles, taking away from the available power I have to throw at resource intensive applications that I might want to prioritize like running a game or encoding a video etc.

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Thank you so much for the detailed responses from all of you.

1. On the Malwarebytes scheduling: It's a tool I downloaded, installed and scheduled to run just for the last 1 week after I first posted on the other forum in an attempt to identify the malware causing high CPU usage. But this issue is something I am facing for more than 18 months I think. Anyway I have scheduled it to run only once a day.

2. I removed Kaspersky completely now using the tool provided.

3. I changed the settings on CCleaner as advised.

After making the above changes, doing a restart and having my task manager open for several seconds, I captured the following screenshot.


The problem is with the Windows Audio Device Isolation service that keeps running all the time despite 'ending task' often. Please note that my CPU fan speed is ALWAYS super high :( So it's hard to convince myself that its just a Windows bug in displaying the wrong % for the initial few seconds.

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<< remarks >>

I can confirm similar experience as Nukecad & Advancedsetup have mentioned above.

On my Windows 10, my Task Manager display settles down after a few seconds;  and gets better the more seconds go by.

Like Nukecad's screen grab, my Task Manager screen had a slew of 0% cpu lines on Task Manager right at its start.


You had Chrome browser open with 17 tabs open.  Do a test by first closing all of Chrome & also any other web browser.

Then start Task Manager.   Wait until at least 15 seconds.   Then look at the display.

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  • 1 year later...
On 10/10/2019 at 3:15 AM, AdvancedSetup said:

Mine does not reach 100% it goes to about 55% on average for less than 2 seconds before it settles back down to about 2% average. I have to be quick on the screen capture to even grab it as it drops back down so quickly





Hey, I guess you haven't plugged in your charger. Try plugging in your charger and check the task manager. For me, when I plug in the charger and check task manager, the CPU usage reduces from about 80-100% to about 1 or 2% within very few seconds. And without the charger connected, it behaves similarly to @AdvancedSetup 's case (From 40-50% to again 1 or 2%). 

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