Ok buddy you want to copy ur contents such as PSN games, DLC's, savegames, images, videos, music to a new hdd. Ok you'll need 3 hdds (2 internal & 1 external usb hdd to do a full backup/restore).
1st you have to backup older hdd (eg 160gb) on external usb hdd (size should be equal/bigger than ur older hdd, eg 160gb) by using backup utility from system settings. Now put your second internal hdd (eg 500gb) in your ps3 format it after formating connect your external usb hdd and restore it by using backup utility from system settings.
You have succefully copied/moved all your contents to new hdd now.
Note : This backup will only work on same PS3 from which the backup has been made.
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