My S3 has only 4GB. Maybe later ones have more. I tried installing the OS update following Apple’s instructions only to find (after hours of installing, restoring, etc.) it still has the old OS. There’s not enough space no matter what, with no photos, music, or apps added. On top of that, my Activity/Fitness stats for the day were messed up and I had to start accumulating stand hours, calories, etc. from zero. What I had for the first part of the day was added to the previous calendar day. (This happened when the watch crashed once, too, breaking my 209 day Move streak for me.)