But, is it an optimal file system to be used with modern USB3 flash disks? Normally, USB flash disks are sold formatted using the FAT32 file system.
?At that rate, the most I will fit on this 750 GB drive is 637 GB (with 0 free space). ?However, on my much larger, exFAT formatted external drive, the difference is 17.38%. On my 120 GB NTFS formatted internal hard drive, the difference is only 0.16%. The drive works fine, but I had a question about the difference between “Size” and “Size on disk.” After drive was formatted, looking at the format options again shows that the “Allocation unit size” is 256 KB.Tried with “Quick Format” un-selected first, but it was taking too long, so I stopped and started over with “Quick Format” selected.For “Allocation unit size” I selected “Default allocation size”.I decided to try exFAT, because I was enticed by the reduced overhead.
?It has Advanced Format Technology (AFT), but I use Windows 7, so I assumed I would be safe. I recently bought a 750 GB 2.5″ hard drive and put it in an external enclosure. Question: Why is there such a big difference between “Size” and “Size on disk”?(9 answers) ?Closed 7 years ago.