Kernel_task: a nightmare... any idea? VirtualCam... ok! but...

[jlm70]

Dear friends,
I'va a Macbook Pro 15 2018 with latest Catalina and OBS.
My extremely big problem is that ANY TIME I start a programme that uses an external webcam (eg. Logitech Brio 4k or Elgato Cam Link with DSLR) the process "kernel_task" (normally using 2-3% cpu) goes in seconds to well over 100% (even 400% or more) transforming the system to... unusable. It happens with OBS, Webex, Teams... whatever programme that accesses a camera stream.
I installed in the past CamMask and Snap Camera, but I removed both of them.
I tried installing latest Norton Antivirus and did a complete scan: no threat found.

I really cannot understand what happens, 'cos kernel_task is a system process, cannot be stopped and... gives me no clue about what is the real program causing this mess.

Any help please? I'm desperate 'cos I really need - especially in this pandemic period - using the camera.

BTW my wife new MBP 16 2019 performs perfectly: installed OBS there and... the evil kernel_task does not even start. Tried even the new MacOS virtual cam and works with Teams... exactly what I would need (OBS in majow web conferencing systems)... :-/

Thanks in advance!

 

[jlm70]

A bit more... if when I start OBS I have the kernel_task at 3-4%, without doing anything - nothing at all, only OBS open - I reach a kernel_task at 300-400% in less than a minute.
If I close other apps, eg. Chrome for instance, it goes back to about 30% and then starts back to rise to 400+%. If I close other programmes, such as powerpoint or dropbox or air server, I go back again to 30% and then... it starts rising again.

If I minimise the OBS window, it goes back again to 25% and... stay there. Not rises again.
If I restore the window, the kernel_task starts to rise again and... I see... together with the WindowServer process (I do not do anything... only opened window...).
If I put the OBS window behind another window, OBS stays at 55-60% and WindowServer to 40%: and they do not rise anymore.

I'm using an external BENQ 27" monitor, but I cannot think this is the problem, given the 560X GPU and 16GB of RAM.

 

[Tangential]

It sounds like a driver issue. Have you looked in the system log to see if you have any errors related to the USB drivers? If nothing stands out, I think I would try booting in recovery mode and reinstall Catalina. You don't lose anything and it only takes an hour or so. Another simple thing to try with a USB issue is to reset PRAM and SMC.

 

[jlm70]

Thanks for the prompt answer. Unluckily I'm less used to MacOS driver management vs Windows. Just upgraded to latest Catalina service pack 10.15.5 SP1 but this seems not to have solved anything. I'll try today with the SMC/NVRAM reset... Than maybe entering in safe mode and verify with kextstat what kernel extensions have been installed. Nonetheless it would be great if somewhere in the system would be visible a detailed CPU monitoring of kernel_task sub processes.... 'cos I think I would sure point out what is rising like hell the usage in well specific moments.

Unluckily reinstalling the OS is probably forbidden by my firm policies (it's an office laptop, with encrypted disk, etc.): is it sure you do not loose anything, with a reinstall? Nothing to install back?

 

[Tangential]

Thanks for the prompt answer. Unluckily I'm less used to MacOS driver management vs Windows. Just upgraded to latest Catalina service pack 10.15.5 SP1 but this seems not to have solved anything. I'll try today with the SMC/NVRAM reset... Than maybe entering in safe mode and verify with kextstat what kernel extensions have been installed. Nonetheless it would be great if somewhere in the system would be visible a detailed CPU monitoring of kernel_task sub processes.... 'cos I think I would sure point out what is rising like hell the usage in well specific moments.

Unluckily reinstalling the OS is probably forbidden by my firm policies (it's an office laptop, with encrypted disk, etc.): is it sure you do not loose anything, with a reinstall? Nothing to install back?

A reinstall just lays a fresh copy of the OS in over the current one. It does not erase anything, but if an Apple driver file is messed up, it will be replaced with a fresh copy.

 

[jlm70]

Ops... I've an idea of what happened... My MBP has been over the last 3 pandemic months always attached to my Benq 27" docking station... and probably Apple batteries did not like to be always power connected: I noticed my cover did INFLATE A LOT!!
Then I opened the back cover and found inflated batteries... so inflated to keep the cover open for 9 millimeters.
Probably the excessive batteries heat did downclock the cpu, giving my performance problems...
Now I'm using it "open" and it does seem to work again... sure I've to change the batteries or Mac as soon as possible...

 

[jlm70]

And... by the way... welcome to the "new normal"... :-D

Lesson learnt: it's not always a software problem... Strange, in all honesty, for an Apple device that has always worked like a jewel.