iPhone 6 64GB = 55GB of usable space?

Discussion in 'iPhone' started by STC, Oct 4, 2014.

  1. STC macrumors 6502a

    May 14, 2008
    Yesterday I returned my 16GB for a 64GB. I noticed after doing a restore from 2 night's ago sync that I have 55GB of usable space. On the 16GB I had 3GB left (which is why I exchanged it).

    Why does the 64GB take up 9GB for iOS, while the 16GB used 4GB?

  2. yeedawg macrumors member

    Sep 28, 2013
    Did you restore from backup? It could be all of your files and what not.
  3. deviant macrumors 65816

    Oct 27, 2007
    Wait what? 16-3=13 used. 64-55=9 used. Am i missing something?
  4. matttye macrumors 601

    Mar 25, 2009
    Lincoln, England
    He's saying he had 3GB left on his 16GB iPhone once he had filled it up, but his empty 64GB iPhone only has 55GB of usable space.
  5. Mercenary macrumors 65816


    Sep 17, 2012
    Also, even without iOS taking up space 64gb isn't actually 64gb when formatted.
  6. rui no onna macrumors 603

    rui no onna

    Oct 25, 2013
    While it's not as bad as that, I still don't get the reasoning for less free space on higher capacity models (even factoring in GB -> GiB conversion).

  7. Menel, Oct 4, 2014
    Last edited: Oct 4, 2014

    Menel macrumors 603


    Aug 4, 2011
    The 64GB versions come out of the box with GarageBand, iMovie, Keynote, Numbers, Pages etc all large apps, all preinstalled. But also deletable.

    edit: just checked through all. Their app store compressed archive size before install is 2.1GB. Could easily expand to 4GB when decompressed + any content from music/video that didn't make it back through the restore process.
  8. STC thread starter macrumors 6502a

    May 14, 2008
    You're not, I added wrong haha. Long night last night.

    • 64GB - 9.5 + 46.5 = 56. 64 - 56 = 8GB used up by iOS 8
    • 16GB - 9.5 + 3 = 12.5. 16 - 12.5 = 3.5GB used by iOS 8.

    The question why does iOS take up more on the 64GB then on the 16GB.
    The same apps are on both devices.
  9. jfyrfytr25, Oct 4, 2014
    Last edited: Oct 6, 2014

    jfyrfytr25 macrumors 6502a


    Dec 6, 2008
    It is because storage drive capacity is calculated and reported slightly differently than other capacities in computing. If you look at the specifications on the back of an iPhone box you will see a note that says something along the lines of ”1 GB = 1 billion bytes. Actual usable capacity may vary.” In other words, the drive capacity is reported on the assumption that 1GB is 1,000,000,000 bytes. So 128 is in other words actually 128,000,000,000 bytes.

    If you are familiar with computers you know that they calculate things slightly differently. Computers count 1,024 bytes per Kilobyte, 1,024 KB per Megabyte, and 1,024 MB per Gigabyte. This means that when you install a 64,000,000,000 bytes storage drive into a computer, that computer converts the amount of bytes into gigabytes by dividing by 1024 all the way up through the scale, not by dividing by 1,000.

    Doing the math, this is what we end up with:

    64,000,000,000 Bytes / 1,024 = 62,500,000 actual Kilobytes
    62,500,000 KB / 1,024 = 61,035 actual Megabytes
    61,035 MB / 1,024 = 59.6 actual Gigabytes

    And that is why a 64GB will be correctly reported by the iPhone as 59.6GB. The larger the numbers are, the larger the discrepancies will be. On an 8GB USB drive the difference between the advertised capacity and the actual is about half a gigabyte, while in our example above the difference is a very noticeable 4.3GB. It is important to understand that these 4.3 GB aren’t lost. The drive is 64,000,000,000 bytes in capacity, and after 64,000,000,000 bytes have been converted into Gigabytes, the total capacity comes to 59.6 GB.

    now add the OS and you are down to your 55GB.
  10. STC thread starter macrumors 6502a

    May 14, 2008
    I notice that when I put all my apps on the 64GB. I deleted the extra apps right away.
  11. Bahroo macrumors 68000

    Jul 21, 2012

    This, they take up a few GB's total.
  12. rui no onna macrumors 603

    rui no onna

    Oct 25, 2013
    Still doesn't explain why OS usage goes up (or factory available space goes down) as you go up in capacity as you might see from my calculations above. There's around 7% disparity between GB to GiB and that's fixed.
  13. Jman13 macrumors 68000

    Aug 7, 2011
    Columbus, OH
    The question has been answered several times now. The 64 GB versions have iMovie, Garage Band, Pages, Numbers, etc pre installed.
  14. rui no onna macrumors 603

    rui no onna

    Oct 25, 2013
    Those didn't come pre-installed with iOS 6 and that's where the numbers I posted above come from. Also, that's Capacity as reported by iOS and not just Available so apps, etc, are already not included. Only thing I can think of to explain the difference is Apple does higher overprovisioning or sets aside more area for cache on higher capacity models.
  15. Potatochobit macrumors regular

    Apr 2, 2011
    you cannot compare iOS6 and iOS8 builds, dude
    they will obviously not be the same size
  16. rui no onna, Oct 4, 2014
    Last edited: Oct 4, 2014

    rui no onna macrumors 603

    rui no onna

    Oct 25, 2013
    Yes, the numbers above are for iOS 6 but they're all iOS 6.1.3 on 9.7" iPads with retina (3rd and 4th gen) which is as fair a comparison as I could get. Besides, what I'm trying to point out here is a trend which the OP has also noticed.

    My iPhone 6 Plus running iOS 8.0 (12A366) reports Capacity of 55.7GB (Settings > General > About). I'm still waiting for better availability on the 6 Plus before I order 128GB. When that comes, I'll post the calculations and comparisons.

    Now if someone has the 6 Plus in 16GB and 128GB capacities (please specify the complete iOS version), then please post the reported capacities for your model here and I'd be happy to make iOS 8 to iOS 8 comparisons.

    Going by the OP's report:

    iPhone 6 16GB: 9.5 GiB used + 3 GiB free = 12.5 GiB capacity
    iPhone 6 64GB: 9.5 GiB used + 46.5 GiB free = 56 GiB capacity

    16GB ~= 14.9 GiB
    64GB ~= 59.6 GiB

    14.9 - 12.5 = 2.4 GiB
    59.6 - 56.0 = 3.6 GiB

    3.6 - 2.4 = 1.2 GiB

    Assuming the iOS 8 firmware uses 2.4 GiB, where did the extra 1.2 GiB go?
  17. d123 macrumors 68000


    Oct 19, 2009
    People have answered your questions more than once.

  18. rui no onna macrumors 603

    rui no onna

    Oct 25, 2013
    And again, that's not the answer. For one thing, this has been happening since before Apple started bundling those apps with iOS. For another, the OP already deleted those apps. Besides, based on previous experience, I'm guessing the 128GB model loses even more storage. In that case, how would you explain the disparity between 64GB and 128GB that goes beyond IDEMA and computer definition of a gigabyte? I'm assuming the 128GB model will also have iMovie, Garage Band, etc pre-installed.
  19. terraphantm macrumors 68040

    Jun 27, 2009
    When I was doing a DFU restore on my iPhone 6, I noticed iTunes said the capacity was something like 59.7GB, which is about in line with what you'd expect for a 64GB device. So at least we know the devices do ship with the advertised amount of flash (unlike macbooks...)

    Now why iOS appears to take more space on the larger versions... I don't know. My only guess is that perhaps Apple makes the root partition larger on the larger devices
  20. rui no onna macrumors 603

    rui no onna

    Oct 25, 2013
    In absence of a better explanation, yeah, that's one of my guesses, too. Perhaps I should check XDA or something to see if they have an answer.
  21. r-m macrumors 6502a

    May 7, 2010
    Doesn't iOS 8/system files show as "used"? When the device is first set up, and ignoring iLife and iWork apps, there's some "used" space from the start.

    I'll restore my 32gb 5S tomorrow night when I get chance, and see what that reports
  22. rui no onna macrumors 603

    rui no onna

    Oct 25, 2013
    Nope. Without any apps installed and no media on the iDevice, it does report 0 used (at least that was my experience on a factory reset iPhone/iPad on iOS 6 and 7).
  23. STC thread starter macrumors 6502a

    May 14, 2008
    Guess I'm going with this answer.
  24. Mercenary macrumors 65816


    Sep 17, 2012
    You've lost more because the larger the disk the more space is lost in the eve whole 1000-1024 marketing thing. See the link I posted above.
  25. Abazigal macrumors G3


    Jul 18, 2011

    And frankly, that answer is rubbish and I am surprised more people haven't called them out for it.

    Pre-installed apps use a different block of memory than the one used to install the core os. Apps like iWork's will not count towards the space used that reduces the storage to 59 gb, so that can't be the reason.

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