MacBook Pro runs much hotter with High Sierra

[simonsi]

Thats only your processes, nothing there but you must have processes running as root or another user, hence the big red area in the cpu usage graph...

 

[Tanuski]

Can you tell me how to run it as root?
Thanks.

 

[maflynn]

Not sure if I am doing it right.

You're only showing your processes, but clearly there are other processes running, just look at the bottom and see the CPU load, its rather high
In the Activity Monitor, click the View menu and then select All Processes

 

[Tanuski]

I see. Now I have change it to 'All Processes".
And I found the 'Ker

nel_task' is dominating the CPU....
So what can I do?
Thanks guys !!
[doublepost=1535237646][/doublepost]A reboot in safe mode (holding down shift key while reboot)....
With nothing running in the background, except Activity Monitor, the Kernel_ task is still acting up.

 

[[AUT] Thomas]

As per your first screenshot you have some 3rd party tools installed. Maybe they have messed up the upgrade. Macsfancontrol and similar tools can cause issues like that (Kernel task also does thermal management stuff). I'd disconnect all hardware (especially DisplayLink Screens), uninstall macsfancontrol and probably the DisplayLink Drivers (the KEXTs shouldn't actually be loaded in safe mode...) and do an SMC reset. Although, uninstall doesn't help if a problem was introduced during the upgrade process itself.
Regardless of that probably try disk utility and first aid on the system drive just to fix any permission issues. That should be done every now and then anyway, especially after any upgrade.

Just to have it mentioned: Depending on the software installed I'd go for a clean reinstall rather than wasting time with troubleshooting. If you happen to have a second mac, the easiest way is to transfer the user profile to that mac, reinstall, preferably to latest OS version, then transfer the userprofile back. That restores only the user profile, but keeps the clean state of the fresh system. Apps need to be installed manually that way, which is, considering the App-Store a quick thing to do...

 

[Tanuski]

Thanks for the advice, Thomas!
For the record, when I run the MacBook Pro without the external Apple monitor, everything work perfectly fine.
In other words, linking an external monitor will slow down the system to a point of unbearable.....