The "box" can't be any stiffer then the solid geometry if its the same material
When you are dealing with wood products, it most certainly can. Probably due to the elasticity of wood.

Consider a cheap hollow core door, with the skins being 1/8" (3mm) masonite, and the core usually a paper honeycomb. It's considerably stiffer than an equivalent thickness masonite board.

Or take a lamination of 3 layers of 1/4" MDF, which is considerably stiffer than 3/4" MDF. (I've tested this in my build thread)