The top or htop commands will show you, by default, which processes are using the most CPU. You can hit F6 to sort to it by this value or "CPU_TIME"...
So far I have installed 24.04 on 14 different computers and had a similar problem on one of them ("no camera found"). I offer this not as a solution...
I have a dual boot system with three HD.
Two of them are solid-state HDs, with Ubuntu 22.04 (root and /home) on the first and Windows on the second....