It can take quite a while, depending on how many phot/vids you have.
Recently sync'ed 16K+ items to an iPad last week with my gig fiber, and it took part of an afternoon.
iCloud will sync. Give it a day, and let us know how it goes.
I find it fascinating to choose "All Photos", and pinch to "zoom-out" so all my (future) assets are just a wall of 7mm^2 icons, and watch 'em appear over time as everything syncs