Request Description

I noticed that in vanilla Minecraft when you move the mouse the fps drops a lot. Here is a video:

This is expected, when you're standing still the renderer has much less work to do to update culling and you become CPU-limited. Your video is of vanilla minecraft; Sodium already improves upon this, and there is ongoing work to improve it further.

the fps changes just from mouse movements, not from camera rotation

Are you able to reproduce this in fullscreen with only Sodium installed? You can use F3+Esc to make the mouse cursor visible

UPD: can reproduce

Please look at the second half of the video, the fps changes just from mouse movements, not from camera rotation. This also happens with Sodium for Fabric

The second frame drop is normal windows actives because your switching from rendering single a single application to multiple in boardless window mode.

Please look at the second half of the video, the fps changes just from mouse movements, not from camera rotation. This also happens with Sodium for Fabric