Please read about Kim Peek - that guy read two pages simultanenously while retaining 98% of the content. He had the content of around 12.000 books in his memory and could recite every page after reading it once.

He was the inspiration for the movie. But he wasn't very happy and felt trapped in his brain because no one was able to have meaningful conversations with him. Poor guy.

Reason for his insane memory is that the connection between the left and right hemisphere of his brain is missing. This means that all the information get saved because the filters aren't working properly.