As a new user to Linux, I’ve run into some issues and I though the thoughts below might be helpful for anyone running in to similar issues.
CPU Boosting Behavior (Observed on AMD 5800X)
If you are are not seeing proper CPU clock boosting behavior in games, it is possible that your version of gamemode requires you to add yourself as a user. You should check this through mangohud overlay in your game - you might notice artificial capping vs. what you may have observed on Windows.
In the terminal run:
gamemoded -t
This will let you know if everything is working or if there are issues and if they are related to your GPU or CPU.
If there are issues, try running the following in the terminal to add yourself to the appropriate group:
sudo usermod -aG gamemode $(whoami)
In my case, my CPU was not boosting as expected and after running this and rebooting normal CPU performance was observed.
GPU Boosting Behavior (Observed on Radeon 7900 XTX ‘Reference by AMD’)
If you are seeing weird clock gating or the power consumption shown in mangohud is significantly below your TDP/TBP, you may be running into a firmware ‘bug’ from AMD that attempted to fix a non-existent problem and instead remains outstanding nearly a year after being reported. In order to prevent underclocking on Linux (honestly how is this even a problem work thinking about???), Radeon erroneously set hard coded maximum power consumption and clock settings below what your card is capable of (and advertised to run at in stock configuration).
In order to fix this, you need to install LACT.
In LACT, go to the OC tab and set your power usage limit to your board advertised / supported limit. In my case I changed it from 290 to 350. From there, you will need to enable the OC support in the software (where it states that it is not supported). Apply that change, close LACT and re-open it. Make sure that your updated power limit remains in place and make sure performance level is set to Automatic. Your maximum GPU clock should have increased probably to something around 3 GHz vs. the 2.3 GHz cap that may have previously displayed. This is fine because by leaving the performance level at automatic, the card will simply revert back to its prior firmware behavior of managing itself based on load. Make sure that for any changes, you hit apply.
In Cyberpunk at 4 K ‘Ultra’ settings, I observed approximately a 12.5% performance increase using the default benchmark. RT Ultra (using performance with frame generation) went from unplayable to fully playable. Path tracing is nearly but not quite playable. Basically, feels exactly like Windows performance again.
As a Windows refugee, I’m still learning a lot about Linux, and I hope this is helpful for anyone in the same situation as I floundered quite a bit trying to figure out what was happening before finally deciding to write all this down and save some instructions somewhere in case I need to reinstall or change hardware.