You are not using the loci method are you? (The memory palace)
It takes me 10 minutes to memorize a deck of cards right now. It took a lot of time to assign characters to my cards and considerable time to set up mental journeys to store the characters. It's a mental algorithm but the setup is not trivial. Maybe you are just gifted but I'll say it for the others, it's not that easy.
Not gifted, but I have a very good imagination. So does my brother, and that's what the method he uses in the book I read is based off of, so perhaps that's it.
