Xbox 360 - Where Did 7 Gigabytes Go?

The waves around Microsoft's new console aren't quiet, and it's even like their numbers are growing.

According to new news, the 20GB hard drive built into the console can only be loaded with 13GB of data, meaning 7GB of storage space is lost somewhere. True, the operating system also takes up space, but it is highly doubtful that it is 7 GB, since a complete XP does not need more than 2 GB by default.
So the question is given! What does the console use the lost, about 35 percent storage capacity? What’s for sure is that only 20 percent of the 65GB of storage space announced in the ads can be used for data storage, which, to put it mildly, makes the announced capacity a strong slip.