I want to take this argument of efficiency in a different direction. First, two key observations: the system doing the simulation will never be as efficient as the system being modeled. Second a conscious system is aware of it's own efficiency. This means even if you simulate a whole human body to create consciousness it will not have the same quality. It will either be aware of all the extra resources required to create "self" or fed a simulation of self that hides it's own nature and thus cannot be self aware.