Brute Force - Snow & Ice Shader Documentation
10. Performance Tips
Probably the biggest performance factor of the snow & ice shader is the tessellation factor of the snow.
You should keep the Tessellation Ice to 1 (which is equal to no tessellation)
For PC/Linux I recommend setting Tessellation Snow between 20 and 50 and for mobile/VR/AR you should stay below 20.
The performance hit is relative to the view distance between the snow and the camera.
Check or uncheck the features you don't need in the material, if you don't need Interactive effect you should disable "Use RT".
Disable Shadow Casting
You might not need the shadow casting feature of the mesh renderer in which case this could save you a good performance chunk. This is especially true for terrains which have a Double shadow casting enabled by default!