Comment 6 for bug 1768976

I had a similar problem. turns out it was actual high load that forced the cpu clock speed to always be more than 3GHz on all (!) cores. namely the xorg (>100%), systemd-journald (>50%) and rsyslogd(>30%) were consuming a lot cpu power. in the journal i could see the following line over and over again:

    SynPS/2 Synaptics TouchPad: Read error 9

After a bit of digging I found that the synaptics driver should be replaced with the xserver-xorg-input-libinput. (which I had already installed, maybe that was the problem)

see: https://wiki.ubuntuusers.de/Touchpad/

So after removing the package xserver-xorg-input-synaptics the cpu load went down significantly and so did the cpu-clock and heat.

problem solved for me