Can you point some known/well documented facts that show how fast first class mathematicians/physicists absorb large volumes of new knowledge in their areas? Or how fast they master it.

Although it would be interesting to see some info on this too, I'm not specially interested in prodigies, like terry Tao.

Although this might not be that much relevant, I'm curious about what kind of grades theses guys get, I can't imagine a guy like Ed Witten being unable to answer any physics question designed for 'normal'(even 'Princeton normal') people.