As I said, it is a balance in the details.
Poly Count versus textures. Both consume memory.

Blender lets you bake the textures ; Bump map, the displacement map and the normal map. (I send you links to tutorials some time ago).

But?
Do not overdo it.
It is pointless to use all 3 (bump, displacement AND a normal map).

Normal and bump map are both "faking" 3D, while a displacement map is the only one that actually "displaces" its micro polygons in 3D space.

Personally, I prefer displacement, but I also use bump map if the object file needs it.

 

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!