What's up with Deja Vu and Photographic Memories?

So I had always wondered, what is the science behind Deja Vu?

After looking into it, I learned that our memory system has two parts: definitive recollection and familiarity level. In Deja Vu, our familiarity level gets triggered, and our brains confuse memories to make it seem as if we already did something we know we haven't done before.

This then lead to another question I had, ever since I heard of Mike Ross (above) on the T.V. Show Suits (amazing show, I highly recommend it), which was why some people had photographic memories. Basically what happens is, as memories get older, they tend to overlap. Therefore, because some memories overlap quite often, our brains get confused and cannot recall specifically what happened over a certain period of time. Now, people with photographic memories are better at separating out overlapping memories, and thus they are able to recall events that happened in the past with incredible detail, as if they had taken a mental snapshot in their head and stored it in their heads.

 I certainly wish I had photographic memory, but I always wondered if people with photographic memories feel more cluttered in their head since they have all that extra, often unnecessary information stored in their head. Is there a limit to the amount of information the brain can store? Scientists have yet to figure out, since there are so many connections between neurons and thus a large capacity for storage.