Yes, kinda. There are also the possibilities of novel types of computation being involved. We know about quantum computers. They can't do things classical computers can't do - but they can do them faster - in some cases MUCH faster. Maybe there are other types of computation - besides classical computation and quantum computation that we have yet to discover. Quantum computation was only discovered relatively recently - so maybe the future holds other possibilities. Gateways to oracles, etc.

It doesn't look as though the brain is anything other than a classical neural network - which could fairly-obviously be ported onto silicon - if we had fast enough silicon. However, there is at least some room for doubt on this point.