A:Answer All of them format to TB, not G(GB?), so when you get a plot of land 100x100 feet, a fence installed to hold various farm animals, say files, takes up space, 1x100 on all sides, so you lose a bit of space. This formats to about 7.68Tb after formatting with NTFS, similar with exFAT and HFS+ for OS X. Learn about this on youtube, search for "why do hard drives format smaller"...