I find that the default settings for the radeon driver that is applied to most AMD cards is horrible. For example by default TearFree is not enabled and it causes videos to have some kind of square artifacts.
Here are the settings I have found most suitable for AMD cards:
You need to create file in the following path and restart Xorg or your computer to apply it:
*Beware that making a mistake here will possibly make your computer unbooable or you will need to use a LiveCD to correct the problem.
sudo vi /usr/share/X11/xorg.conf.d/20-radeon.conf
Then paste the following and save it:
# Set Driver "radeon" because xorg now uses the modesetting driver by
# default for Radeon HD GPUs and it causes a lot of triangular tearing.
# We don't need TearFree to avoid tearing in Chrome and mpv; TearFree also
# has the disadvantage of making switches to text VTs take 2 seconds.
Option "TearFree" "on"
# Use the default exa; glamor causes subtle but visible triangular tearing
# when used without TearFree.
Option "AccelMethod" "glamor"
# DRI3 is not enabled by default on my Radeon HD 6470M
Option "DRI" "3"
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