What Is Shader Compilation and Why Does It Make PC Games Stutter?

howtogeek.com:

Some games have a type of stutter that happens no matter how powerful your computer is, or which settings you choose. This is caused by a process known as “shader compilation,” and it’s a growing issue in PC gaming.

Shaders are computer programs that help determine various aspects of rendered graphics. Pixel shaders, for example, calculate the attributes of a pixel. This includes the color, brightness, reflectivity, or transparency of that pixel. If you want something in your game to look wet, you use a special shader to achieve that look rather than do it painstakingly by hand.

Shaders are what make modern GPUs so flexible since these GPUs are designed to run anything that can be expressed in shader programming language. They replace the old “fixed-function pipeline” GPU technology where the types of graphical math a GPU could do were hard-wired into its silicon.

“Compilation” is a computer term that refers to taking the code as written by a human programmer and translating it to machine code that the specific processor that’s meant to run the software in question can understand. So, for example, you might compile your code to run on an Intel CPU or Apple Silicon.

The same thing is necessary for a GPU. The shader code must be compiled to run on the specific GPU brand and model in question. If you change the GPU, update its drivers, or the game receives an update, the shaders must be compiled again.

In some games, compiling shaders in the background interferes with the game itself, causing a visible stutter. The computer is working too hard at compiling the shaders to run the game smoothly. Some developers labor to optimize compilation so that it has little or no impact on game performance, while others spread shader