Yesterday I upgraded my old 60GB PS3 HDD to a 320GB Samsung Spinpoint M7 HDD. Everything worked just fine, but there's one thing that really bothers me:

On my old disk were about 25GB, so when I did the backup to an external disk, there were almost exactly 25GB on it.

When using the new disk, I formatted it, then restored the whole backup to it, and in the systems information I get told that on the disk there's 239GB/298GB free. So that would be 59GB, instead of only the initial 25GB. More than the double!!

What's wrong? Does the PS3 f.ex. reserve a certain % of space for a disk?