Is Rios really THAT much bigger than Gamboa?

I tend to agree with the idea that Gamboa will outclass Rios early, but typical of Rios he takes the punishment and starts breaking Gamboa down and stops him. Gamboa's been put on the deck by little guys, I imagine Rios would be fully capable of hurting Gamboa at some point. I also agree that Gamboa's power may be overrated. Bob Arum is cashing Gamboa out to build up Rios.