Here is what I found after getting the back off and pulling the stock 1gb card, the PDN still run without it. Apparently, there is another 1gb of memory somewhere inside the machine where the root files are stored and run from. I'm not even sure why they even have it in. It was only being used as storage for the book reader.>>>bryan_d you have more internal storage for books.. about it. Prolly won't see any real performance difference other than book load times.