Should I actually model the bevel for my mesh object, or use bump mapping?

Which is truly better for memory and performance?

If I have a plain hexagon slab model, with up to 10 instances on screen at the same time; and if I use bump mapping to create the beveled look, would that not be more expensive because of the added bump textures and rendering work as opposed to actually modeling the bevel itself?

I don't have Unity Pro so can't really use the profiler to know for sure.

Thanks, Manny