Since recently I started to get very heavy CPU load on my 64bit Debian 9.0 Cinnamon machine. I have all my packages up to date including Firefox-ESR. Often the load is so heavy that I can hear my CPU.
I also get it when restarting the browser in safe-mode. I did not get CPU load spikes before restoring my session for the time I tried.
I also did a ClamAV scan like so:
clamscan -r --bell -i --exclude-dir="^/sys" / -l clamav1.log which tells me infected files are 0. And rkhunter also tells me that there are no rootkits.
Early screenshot of system monitor (also I don't know how listening to soundcloud & youtube can upload so much data but that's another question I guess?): When I open about:performance to check what causes the load that very tab 'seems to be it' (note the CPU usage percentage): In safe mode:
I also get this when having just one tab open. Could tabs that aren't even loaded be causing this? Any ideas what might cause this or any suggestions for things that I could try? Note that I'm relatively new to Linux/Debian; also I'm not that sure if this would fit better into unix.stackexchange.