After a Ryujinx update, delete your old shader cache. Old caches often cause graphical glitches (rainbow colors or invisible characters).
Stop the Stutter: A Complete Guide to Precompiling Shaders in Ryujinx ryujinx precompile shaders
If you have ever tried to play Tears of the Kingdom or Pokémon Scarlet/Violet on Ryujinx, you know the pain: The game freezes for a split second every time you swing a new sword or enter a new area. After a Ryujinx update, delete your old shader cache
Have a specific game stuttering? Drop the name below. After a Ryujinx update