how does Ophelia's real madness differ from hamlet's feigned madness?

Ophelia really has gone over to "Crazytown". Her rants and snippets of song only make half-sense. They allude to the stresses in life that she can no longer handle. She also really looks the part. I have seen some pretty ragged looking Ophelia's in performances over the years. Hamlet has method in his "madness". His witty rhetoric is calculated and targeted at specific people.