I am having huge performance issues on a relatively fresh (few days) install of EndevourOS.
I first noticed that watching a twitch-stream in Firefox uses up 200% CPU, which obviously is not right. It is not a twitch issue, since the same happens on YouTube and it is not a Firefox issue, since on Chromium I have 150% when watching Twitch.
For some reason now the numbers have gone down slightly in Firefox. Watching a stream uses 50-120% (instead of 200%) in one firefox-thread, 30-35% in another and 30% for Xorg. For Chromium it is 125-150% in one thread, 40-45% in another and 40% for Xorg.
I also tested out running Steam games and I have horrendous performance there as well (Slay the Spire running on 15fps with 300% CPU when it was running just fine on my previously installed Antergos). I also had very bad performance when enabling transparency-blur under i3, but I initially thought my machine was just not able to handle that (which it probably should though).
It seems like a graphics driver issue, but I was also under the impression that Firefox did not have hardware acceleration anyways and decoding on the CPU should not bring my machine to sweat. I have installed the NVIDIA drivers through nvidia-installer-dkms and nvidia-settings tells me that driver version 455.28 is installed. glxgears runs with a bit over 1k fps.
I do not think this is a hardware issue, since everything is running fine under Windows.
I am running LightDM and the problem is the same in Xfce and i3, which I have both installed through the OS-installer with all their respective packages.
I definitely do have both 5.9 and 5.4 installed. I installed linux-lts and can also boot into it. When I put dkms status -k in bash it autocompletes to both versions, further suggesting that I have them both installed.
$ dkms status -k 5.
$ pacman -Qe | grep linux