Leeching dozens of free materials from https://3dtextures.me/
Default UV sphere works better for previewing adaptive displacement materials if the UVs are scaled like this.
Materials intended for use on a flat plane don’t look so good on a uv sphere without adjusting texture coordinate mapping scale and then you have to set the scale back to [1,1,1] when you actually want to use the material. Easier to just scale the UVs of the sphere and leave the mapping scale at 1.
It seems normal maps override displacement maps:
With both active I think only the Normal Map is seen.
With the Normal Map disabled the full strength of the overly strong Displacement is seen:
With almost every material the Displacement value looks best at 0.01 when doing actual 3d displacement.
All of the free materials are only 1024x1024 so their normal maps look like something out of a video game. Most of the time it’s best to disable the normal maps and only use the displacement map as bump.