iPhone 5 has 1 GB of RAM, iPhone 4s has 512 MB. iPad 3 has 1 GB, iPad 2 has 512 MB. Obviously, you cannot use all of this. You should definitely not transfer more than 600 MB to newer devices or more than 300 MB to older devices. Good news: you're far, far below that.
, : , 600 iPhone 5. , , 400 . , , , , . , , , , . , , .
, 18-26 . 40 iPhone 5 20 iPhone 4s.