music files saved twice?

[synchronicityii]

how come music files are saved twice on my harddrive? there's one file in my music folder, then another file, that's the same file extention and size save in my itunes music folder? the only difference between the two is that in my itunes music folder, there is a track number right before the song name. but other than that, it just seems that all my music files are saved twice, and taking up twice the space on my harddrive.
another followup question, i have a 250GB harddrive, and i'm only using 40GB of it. does the more music and photos i save on my harddrive make it run any slower?
thanks.

[kingfoot]

It's because in iTunes you have the option of transferring music files added to the library, and you seem to have this option on. To stop this from happening, open iTunes, go to preferences -> advanced -> and you should see a check box that says 'copy files to iTunes Music folder when adding to library'. Or you could simply delete the files you added since they have been automatically transfered to your iTunes Music folder.

Hope that helps