Sonoma Maxing Out CPU

1 - Restart in Safe Mode. This will perform a Disk Repair, clear cache files and only load Apple Software, extensions and fonts. The boot up will be slow and can take some time - Normal.

2 - Safe Mode will also eliminate Third Party Software, extensions and drivers from loading. It will only load the Minimum amount of Core Apple Processes to allow the the computer to function at a reduced Level of Performance 

2A - As you have already experienced in Safe Mode - the issue seems to have stoped only to returned in Normal Boot-up

3 - There could be something in the main User Account playing up. To further isolate this - Set up users, guests, and groups on Mac. Then log out of the Main User account and log into the dummy account and test again if the issue persists.

4 - If the issue is present in the dummy account - then, this appears to be a System Wide issue on the computer.

5 - Download the Application Etrecheck directly from the Developer.

The Application is Not a " Silver Bullet "  and is  only a tool to examine the Hardware / Software used on this computer 

This is a Diagnostic Tool that makes no changes to the computer Hardware / Software used on this computer 

The application is free or paid from added features. 

The Report will Not Reveal Any Personal Information. 

Post back the Full Report - copy and paste - >>>> using the Additional Text Icon ( 3rd Icon to last ) <<<<

The Computer is highly personalized ( modified ) by the Third Party Applications used on the computer

Some of this software is causing " Runaway user process - A user process is using a large percentage of your CPU. "

For that specific issue, suggest to review your existing third Party Application for more current versions designed for or compatible with macOS 14 Sonoma

Also noticed running Sonoma 14.1.1

There is a newer update 14.1.2 but may wait for the Pending 14.2 Sonoma which may appear soon. Only Apple Knows when it will be ready

Hardware Configuration showing as per below. The More RAM the more Application can be keep in RAM for quick and easy access

If going that route, have it done be the Professional

8 GB RAM - Upgradeable

    BANK 0/ChannelA-DIMM0 - 4 GB DDR4 2667  

    BANK 1/ChannelA-DIMM1 - Empty   

    BANK 2/ChannelB-DIMM0 - 4 GB DDR4 2667  

    BANK 3/ChannelB-DIMM1 - Empty   

Still on Hardware the Drive

The drive is a Fusion Drive and is inherently slower than an ALL SSD drive

SSD Drive have no moving parts and do not need to be written to in the same was a Rotational Drive

disk0 - APPLE HDD ST3000DM001 3.00 TB (Mechanical - 7200 RPM) 

disk1 - APPLE SSD SM0128L 121.33 GB (Solid State - TRIM: Yes) 

disk1s2 [APFS Fusion Drive] 120.88 GB

In summation, the RAM and Fusion Drive would be the biggest impediment to have a more responsive computer

That and some of the Third Party Software that may need updates or upGrades to match Sonoma

Try Resetting the SMC of your Mac - Apple Support

Thank you

Yes I see the report

Will have good look

Get back to you on Saturday at earliest