Mobile shader, optimization bugs?

Question

C++ / C#

Hello.
For the unit, I'm making a sky shader, a lot of functionality with one shader.
And I noticed such a topic, if just the sky with painting = 59 fps
If I add clouds on top (just one 1k texture), the fps drops to 50. I don’t understand why, maybe because there are a lot of primitive checks like if else ?
What is wrong?

Answer 1

if-else for shaders is bad, yes.
But the reasons for the crash can be very different - you should at least look at the shader code. Well, it's worth profiling.