When going from 6.8.3 to 6.9 RC2, I had something similar happening to me.
My CPU was stuck in power save mode on 800MHz, resulting is 100% on multiple cores.
I had to put my the "CPU Scaling Governor"-setting to Perfomance using the Tips & Tweaks plugin.
However, with the issue above solved, it happened again when booting a VM. For some reason when I upgraded, my VM broke and I ended up deleting and recreating it.
constant 100% cpu usage on 2 cores.
in General Support
Posted
When going from 6.8.3 to 6.9 RC2, I had something similar happening to me.
My CPU was stuck in power save mode on 800MHz, resulting is 100% on multiple cores.
I had to put my the "CPU Scaling Governor"-setting to Perfomance using the Tips & Tweaks plugin.
However, with the issue above solved, it happened again when booting a VM. For some reason when I upgraded, my VM broke and I ended up deleting and recreating it.