Actually I spent some countless hours to try to debug this. No process seem to work in background. It only occur at the 10th minute of uptime:
- If at this time the PC is idle, then the kernel_task will go crazy forever (hours and hours), until the computer goes to sleep and wake, then everything is back to normal forever.
- If at the 10th minute there is a little bit of load (not much, a browser with a YouTube video is enough), then nothing happens and there won't be any kernel_task issue until next reboot.
It happens on Monterey and Ventura beta the same way (except that in Monterey the kernel_task runs on the first CPU core and in Ventura in second CPU core). I think it is more related to opencore or one of the kext extension in conjunction with my CPU type (i7 9700), but it's way beyond my skills level !
(Occurs on fresh macOS installations with zero apps installed!)
For instance, see the attached pictures.
Picture 1 : 9 minutes of uptime with no load. Everything is normal, kernel_task is at 1.2% (CPU temp is cool at 29°C)
Picture 2 : uptime is now at 10 minutes. Kernel_task goes crazy at 69 and the temperature will rise up to 60°C within the next couple of minutes.
Which event triggered this thing at exactly 10 minutes ? That's a pure mystery to me.