I downloaded this free material but I can’t get it to look exactly the same in Blender.
I’ve tried UV Sphere, Icosphere, rounded cube.
I’ve played with the dicing scale and the displacement scale and mid level and it still looks nowhere near as good.
Are you remembering to change the bump type in material settings to displacement and bump?
EDIT: You will probably need to turn the displacement scale way down, too.
Yes but I can’t find the magic decimal value that looks even remotely close to the demo image. I suspect not having enough geometry might be a bigger issue that the specific displacement scale value.
I would also like to figure out how to exactly match the texture placement but I have no idea what the geometry is that is used in the demo image. It doesn’t seem to be a uv sphere or ico sphere or rounded cube.
The displaced geometry in the demo image does not pinch/shrink at the poles like on a uv sphere at all.
My result (Eevee). Cube Sphere and 1.5M faces. I used VSHADE.
25K faces with Height + POM (Parallax Occlusion Map):
Ha, ha this is probably best way. Who know maybe they answer. In general it’s difficult to get exactly
same result. Render engine, light setup, fine tweaking of material… I remember that I newer get same result with Real Displacement textures https://www.rd-textures.com/product-category/freebie/ although use same software and renderer 
I hear about POM… I wonder can this be used in vanilla Blender, and how?
PS. Blender, Octane… I don’t spare polygons, this is quad sphere with over 1300 poly. Some post process in Octane.
Looks great, but my question would be if I need that may polys to get the wall texture like that, how many do I need for a whole scene, with a garden some grass, plants and of course a main character of interest?
I think I would go for the normal map/bump map version, unless the scene was a close up of a lizard on the wall! 
Your lighting setup is not as bright as the texture preview. Notice how yours doesn’t have any significantly bright areas or shadows? You won’t be able to get the material the same as the preview without matching the surrounding lights.
Why ya’ll going for quad-sphere and not UV-sphere?
Because the texture is “pinched” at the poles in a sphere at the poles (try it!)
1300 poly for displaced sphere are not So Many… Oh, I can make it with less. Octane don’t need subdivision / loot of poly. He use some trickery. This is only one poly, and I little exaggerate displacement.
If you wish to use loot of displacement Octane is way to go. Cycles eat to much resources. Well, I love Cycles, he have many advantages, but Octane much better handle displacement, volumetric, caustic… so for some project he is much more appropriate.
Even the quad-sphere is not perfect. It has seams and slight distortion at the poles. Erindale showed one of the best ways (I think) to present materials here
This sphere is a silly example. Such a texture would never be that curved. (I didn’t get the Quad-sphere to line up yet.)
Talking about sphere great Peter Stammbach make one sphere which can be useful in some cases. Combination of UV and Quad sphere. _Shere.blend (937.3 KB)
Ico have best distribution but triangles can make mess when you subdivide.
Adaptive Subdivision with Microdisplacement was a huge breakthrough and created much hype but still is quite slow (and experimental 
)
That freaks me out. It’s like hybrid corn! But it might come in handy, thanks. What do you call it?
