Same for me: ubuntu 18.04 just installed on Dell Precision M3800.
Before I was on 16.04 and CPU temp during normal session was about 47-55 deg.
Now, it's constantly at 63-80 deg.
I tried lots of tweaks (install thermald, tlp, cpufreq-selector, etc). Nothing worked until now. I'm seriously considering to go back to 16.04, or switch to anything else that would not slowly kill my hardware.
Same for me: ubuntu 18.04 just installed on Dell Precision M3800.
Before I was on 16.04 and CPU temp during normal session was about 47-55 deg.
Now, it's constantly at 63-80 deg.
I tried lots of tweaks (install thermald, tlp, cpufreq-selector, etc). Nothing worked until now. I'm seriously considering to go back to 16.04, or switch to anything else that would not slowly kill my hardware.