Seems from what I can find on Google that people with that condition can remember extreme detail but with many limitations. Does not seem they can remember everything that ever happened to them, like a conversation they had with their mother age 5, the questions and answers they put in high school, what was in the article they read 13 August 2009 at 11 am in the morning word for word etc. I would still say that would drive you insane, for at least some definition for which you could not actually function in society.
I did read about someone with that kind of recall, sufficient to remember all the number plates that passed the car on a trip 5 years ago. i am well out of my area of knowledge and understanding here though, so this is all rumint/hearsay.
