Question What is the difference between Standard material and mobile diffuse materials?

What is the difference between Standard materials and mobile diffuse materials?
Does it increase performance?
And does it affect the graphics quality?

 

Yes.

Yes.

Unity's Standard shader is a PBR, or "physically based rendering" shader with normalized specular and diffuse shading calculations. It is a complex shader, though modern desktop GPUs should have no problem using it on everything even with all of the features ticked on. Also somewhat unintuitively, the Standard shader is potentially more expensive when using baked lighting than real time lights.

The mobile diffuse shader is using very basic per pixel Lambert diffuse shading. This very nearly the cheapest way possible to calculate lighting on a surface. The only thing cheaper would be the Vertex Lit shader (which also uses Lambert diffuse shading, but only calculated per vertex). This was cheap even on the very first GPUs ever made, let alone modern ones. It has no specular lighting, and the Mobile Diffuse version has no support for additional per pixel lights, so after the first directional light all lights are calculated per vertex only.

The short version is Unity's Standard shader is intended to look very realistic and replicate real world surfaces as well as possible while still being a reasonable cost for most modern GPUs (at least those made in the last 5 or so years).

Mobile Diffuse is intended to be as cheap as possible while still having something resembling lighting.

 

Thank you so much