Thanks for the information.
I can see that your CPU is running at a very low frequency(798Mhz) while being fully loaded. This is not OK, and if the reported frequency is correct, it explains why you cannot watch the video. I can also see that your system is running the intel_cpufreq scaling driver instead of intel_pstate. There have seen several reports mentioning this as an issue, resulting in decreased CPU frequency.
Set CPU scaling driver to intel_p-state
[SOLVED] No intel_pstate driver since kernel 5.8.
Therefore I would start by checking whether enabling the intel_pstate driver improves the issue.
Force the kernel to use intel_pstate driver by using a kernel command intel_pstate=active:
- open grub config file by tiping
sudo nano /etc/default/grub - insert
intel_pstate=activeinGRUB_CMDLINE_LINUX_DEFAULT, so for example it might look like this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet apparmor=1 intel_pstate=active security=apparmor udev.log_priority=3" - save using CTRL+S and exit using CTRL+X
- update grub by running
sudo update-grub - reboot
- verify that the scaling driver is active by running
tlp-stat -p. You should see that
/sys/devices/system/cpu/cpu0/cpufreq/scaling_driver = intel_pstate
Afterwards, check your CPU frequency, and CPU usage and please report back. Test it with both webrender enabled and disabled (and remember to restart firefox when switching).
Another option - if this does not improve the situation - is to change the scaling governor to performance, but I would personally wait and see whether this brings an improvement.
Regarding the use of webrender in Firefox - in my case, it actually results in more lost frames because it increases GPU load, (however overall it results in a smoother browsing experience). Just keep this in mind and preferably test the system with both configurations.