Rev. A 64GB SSD shows up as 59.68GB in Snow Leopard?

Discussion in 'MacBook Air' started by voodoofish, Aug 31, 2009.

  1. voodoofish macrumors regular

    Jan 6, 2004

    Sorry I wasn't sure whether to post this under OS X or MBA forum but settled on this one in the end. Also I searched but couldn't find anything so hopefully this isn't posted anywhere else.

    I have a Rev A MBA with the 64GB SSD, and am just wondering why it shows the capacity as ~60GB under Snow Leopard, when I'd thought it was supposed to show the capacity as it is marketed as, ie. as 64GB? I read somewhere that there is also some capacity taken up by partitioning, but doesn't 4GB taken up by partitioning seem like a lot? I just thought I should ask since I don't really understand... :confused: I found another thread but then it seemed like the person only lost 1GB due to partitioning, and that was on a 1TB drive, meaning they were loosing far less of the drive's capacity as a % than I seem to be.

    Finder shows the capacity of my SSD as 59.68GB, System Profiler as 60.02 GB (60,022,480,896 bytes), and Disk Utility as 60.02GB.

    Thanks :)

    EDIT: just to make it clear I understand all the base 10 vs. base 2 stuff, it's just that under base 10 in 10.6 I don't understand why my SSD doesn't show up as 64GB.
  2. CastrolSyntec macrumors newbie

    Jul 7, 2008
    Its Binary


    Its an annoying thing but its caused by the binary 0s and 1s on the drive (SSD HDD and Flash alike) its cimpletely normal, but very annoying. Usually theres a hidden partition aswell, which contains the Drive information, but it cannot be deleted. It is however normal to have less space than advertised, as its the limitation of binary 1s and 0s. Its the same on my iPhone as it should be 16GB, but really, its only 14.5 or something like that.

    Hope this clears it up for you!!!! :)

    - JS
  3. ayeying macrumors 601


    Dec 5, 2007
    Yay Area, CA
    All SSDs have a buffer of space that is allocated in case the cells in the main usable area are damaged from overwriting or other problems.

    128GB SSDs only have ~121GB worth of usable space
    64GB SSDs have ~60GB worth of usable space
    256GB SSDs have ~250GB worth of usable space
  4. voodoofish thread starter macrumors regular

    Jan 6, 2004
    cool thanks for explaining :) obviously in Leopard it showed less than 64GB (and less than 60GB) but I'd always assumed it was just because of base 2 thing and didn't think any more of it (and the same with my iPhone - although of course that doesn't run Leopard/Snow Leopard but you know what I mean!).

Share This Page