That depends on whether or not you are equating the ability of intelligence to the condition of being "smart". If your definition is that they are one in the same, then I agree with you, and I would be wrong. If your definition of "smart" is only the knowledge you posess at any given moment, then computers can be "smarter".
To have intelligence, it must be able to learn through experience. Experience is shaped through perception; perception through senses. For instance, machine cannot "understand" something abstractual, such as music, without being able to sense it in a manner that is close to the way we do.
If we simulate biology, would we be able to simulate sensory reactions as well? Or would we have to actually replicate the biology? Would a machine be able to appreciate "illness" and "death" and understand it on a level we do without experiencing it first-hand to some degree? Would it be possible to simulate such things, or can it only be replicated?
Would such a machine be considered to be "alive"? If we replicate the biology, wouldn't it no longer be a machine?