Sometimes, you don't want to play through the first hour of a game to build up a cache just to get smooth performance. This is where come in—users share their fully built cache files.
Optimize Your Gameplay: The Ultimate Guide to the Best Ryujinx Shader Cache Settings
A shader cache is a database of previously compiled shaders. The second time you encounter that effect, Ryujinx says, "I already did this work yesterday" and loads it instantly. Over time, your personal cache grows, and the game becomes smoother.