When overheating (When fov is wobbling out of control) the fps drops to single digit like straight to 5-6 FPS. Only happens when overheating.

Using latest build of 1.20.1 of this mod on forge.

From what I've gathered, the blurry shader doesn't work well with some graphics drivers. If it causes lag, you can disable distortion effects in the config menu.

From my testing, it reduces my FPS by about 20%.