a lot of hdd are actually sized a little bigger than it is listed as having. This is taken up by what is termed as" lead "in. This is the same as the burn in and lead spaces on an audio CD. The difference being that the system builders are now utilizing this space for thier systems bios and signatures and information pages and the likes and when they get through then you have the amount that was advertised. In your case you get to access that much more form it.