Perfect memory may be a product of OCD

I've always said that memory is a product of attention. I have a better memory than most people I know, and I also pay attention more than most people I know. For people who aren't paying as much attention, more passes are required to give the same amount of attention to the same thing.

Here's another article that supports the idea: http://www.wired.com/medtech/health/magazine/17-04/ff_perfectmemory