[Q] when trying to backup through TWRP my data size is 4.5G !!!! how could it be topic

hello

I move from Nexus S to Nexus 5
I am familier with TWRP and backing up my device
but i have never had to clear almost half of my storage for backing up my device
and i used to fill it with lots of app some of them with additional files over 1G (Asphalt 7 for example)

i can guess it maybe because of file system or something like this,
as in the Nexus S you connect your system to the computer in a different way and could move apps to SDcard and now everything is in the same place so the "data" get very large

so what one should do? should i uninstall large apps ? should i move titanium backup files ?

it all sound ridiculous to me cause it misses the point of the backup :rolleyes:

please Help