No need to format the HDDs Fat32 to have them work Mine is formated NTFS and I hold more then my wii games on it without problems. Just need to use a recent version of GX Loader to read from NTFS formatted drives and you can use something like Wii backup manager to copy files to the drive in a way that the usb loader can use. I keep my games in wbfs format and its possible to get them there using wii backup manager. I use a My Book Essential Edition 2.0 640gb version with my wii but I would assume most any recent external drivers would work with the wii. that includes those small external drivers that have a 2 and a half inch HDD in them.