Brute Force - Ground Shader Documentation
10. Performance Tips
Probably the biggest performance factor of the ground shader is the tessellation factor.
You should keep the Tessellation Tiling below 10
For PC/Linux I recommend setting Tessellation Ground between 20 and 50 and for mobile/VR/AR you should use the NoTessellation shader variant.
The performance hit is relative to the view distance between the ground 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". You can enable "Use Low End" when you need an extra performance boost.
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!
Decrease Render Textures Size
If you notice some fps drops when using the RT effects, then you might consider reducing the Render Texture size, by default the size value of the main RT is 4096 but you can scale it down to 2048 or even 1024 if you don't need high precision effects. The Additional RT is set to 1024 by default and is reasonably small enough:
Keep in mind that decreasing the RT size will also reduce effects definition, so you might want to also scale down the main RTCam Size value: