What does a promotional model do?

What is the difference between shader model 3.0 and 4.0?

• I have seen the difference between shader model 2.0 and 3.0 and basically the 3.0 makes items like cars shine and some items are brighter. But what is the difference between shader model 3.0 and 4.0? Like if I saw two the same pics and one is shader model 3.0 and one is 4.0 what will be the difference? My video card is able to do 4.0 so I just wanted to know what's the difference. I have games that use 3.0 but don't have any that use 4.0 so I don't know what's the difference. I know that shader model 2.0 and 3.0 is for directx 9.0c and shader model 4.0 is for directx 10 and shader model 5.0 is for directx 11. But I just want to for now know the difference in 3.0 and 4.0 since that's what my video card is only capable of.

• Answer:

  http://en.wikipedia.org/wiki/High_Level_Shader_Language#Vertex_shader_comparison