geometry in cycles?

Hey to make realistic textures in the default render engine you can use the ‘‘geometry’’ to make the texture 3D looking, and it takes no GPU memory or anything at all, but in cycles you must do normal mapping, and normal maping requires like 500 faces on a plane to look good, and that takes soooo much memory,
is there anyway to use thegeometry in cycles or any other way to make low poly 3d textures?
Thanx in advance