I had this same issue in my last attempt to upgrade (with a clean install) from 16.04 LTS to 18.04 LTS. When I am browsing internet and specially when I am playing videos my CPU+GPU raises to fast to high levels causing throttling to fire and producing intolerable lags, leaving the system unusable for about 60 seconds or more.
With Ubuntu 16.04 LTS I never experienced this problem. Of course temperatures raised and throttling fired frequently (after all this is a laptop), but system was never unusable and video playback was smooth.
My previous solution was to downgrade to 16.04 LTS again, but now I need the newer version so I want to find a solution.
- CPU: Intel Core i7-6500U
- GPU: Intel HD Graphics 520
- Ubuntu: 18.04 LTS
- Linux: 4.15.0-30
- Mesa: 18.0.5
- Hardware acceleration: on
Definitively it is a problem with frequency throttling. Instead of throttling CPU frequency to avoid overheating the procesor, the system is waiting until temperature reaches a limit (default of 85ºC) and then
intel_powerclamp module fires, turning the system unusable for 60 seconds or more.
I would expect a progressive performance degradation from
intel_powerclamp, but no, it is all or nothing. ¿Can this be configured?
My current solution is a modification of the script of this answer. It seems to work, but it is a big hack. There must be a conventional way to tweak system configuration to accomplish the same result.
If I turn off frequency turbo boost (
echo "1" | sudo tee /sys/devices/system/cpu/intel_pstate/no_turbo) the problem completely disappears. Temperature never reaches the limit and the script introduced on update 1 nor
intel_powerclamp fires and the laptop is smooth and usable.
Problem now is that turbo boost is disabled. With Ubuntu 16.04 LTS I never had this issue.
This is clearly a bad configuration of the thermal management subsystem of Ubuntu 18.04 LTS. Is there a way to fix it?
System is still unusable. Installing Ubuntu 18.04 LTS server and anything else than Gnome3 works. Well, it's not a novelty that Gnome sucks, but it was usable with 16.04...