High CPU Usage (& fan noise) Drop Drastically on Opening Task Manager

Susie1 · 21 Mar 2017

I am using Windows 10 in ASUS ZenBook UX305. The fan of my laptop runs quite loud in general but it drops down drastically every time I open the task manager. The sudden drop in CPU usage can be seen immediately after opening the task manager. I have run Malwarebytes and Eset online scan and quarantined the threats found. But the suspicious behaviour of CPU usage has not changed. Please help.

Caledon Ken · 22 Mar 2017

Hi Susie1. Welcome to the TenForums @Susie1

The next time you notice this happening can I ask you to check your event viewer for the system and see what kind of Errors you are getting. I think you can skip the Information items and likely even the warnings. Looking for the substantial things.

Ken

Looey · 22 Mar 2017

Susie1 said:

I am using Windows 10 in ASUS ZenBook UX305. The fan of my laptop runs quite loud in general but it drops down drastically every time I open the task manager. The sudden drop in CPU usage can be seen immediately after opening the task manager. I have run Malwarebytes and Eset online scan and quarantined the threats found. But the suspicious behaviour of CPU usage has not changed. Please help.

There is a utility called HwMonitor that is free to download. It will display the temperatures in your computer. Do a search for it and you will see it is located at cupid.com/hwmonitor.

It would interesting to see the temps before task manager is started and after task manager is started. It would be helpful if you could see if there is a program that stops when task manager is started. It is a very strange problem. In the past I've seen a virus that wouldn't allow the task manager to be started so a task couldn't be stopped but not one where the task stopped itself when task manager is started so it can't be detected.

theveterans · 22 Mar 2017

Susie1 said:

I am using Windows 10 in ASUS ZenBook UX305. The fan of my laptop runs quite loud in general but it drops down drastically every time I open the task manager. The sudden drop in CPU usage can be seen immediately after opening the task manager. I have run Malwarebytes and Eset online scan and quarantined the threats found. But the suspicious behaviour of CPU usage has not changed. Please help.

I suspect you still have a little critter that actually forces the CPU to go high unless Task manager is opened

ArazelEternal · 23 Mar 2017

It sounds like a virus I had once. Evey time the task manager was opened, CPU usage dropped like a rock and a bunch of processes would disappear. I never figured out what the processes were, but it was fixed by an offline virus scan.

Download this: Rescue Disk for Windows | Comodo offers Free Rescue Disk Software

Burn that image to a CD/DVD and boot the computer from it. It will perform a offline scan of your computer where the OS drive isnt active. This can make it more likely to detect things that are there and remove them for thouroughly.

BradTheGeek · 23 Mar 2017

ArazelEternal Is probably correct. Many viruses and rootkits attempt to stop thier processes when taskmanager is opened. When closed they run, increasing CPU load and with it often temps and fan speed.

I would try tdsskiller and MBAR (not MBAM) first and see what happens. In a pinch you can also do an ofline of Windows Defender/Sec Essentials or the emsisoft emergency kit. Before doing any of that, backup important files to another drive or device. You may wind up having to reset the PC.

Caledon Ken · 23 Mar 2017

There was also two other members that had high disk usage and high CPU and it was a simple error caused by Shadow copy. In one, once we deleted the older data sets everything went back to normal. Hence the request to review the Event log. Could very well be a bug as suggested so not disagreeing with the scans.

Ken

Susie1 · 30 Mar 2017

Thank you all for pitching in.

After debugging my laptop with quite many anti-malwares, anti-spywares and a few anti-viruses, I downloaded a software to observe the CPU temperature. It turned out that the sudden drop in CPU usage right after opening the task manager is only because of the momentary spike in CPU usage for opening the task manager, no other reason.

As for the sound of the fan, after debugging my computer, now its sound remains consistent even after opening the task manager. Even at CPU usage around 10%, it continues to stay loud, at least by my definition of "loud". For this reason, now I'm trying to find a fanless model to buy.