HD Question

Discussion in 'Mac Pro' started by G.Kirby, Apr 25, 2007.

  1. G.Kirby macrumors regular

    G.Kirby

    Joined:
    Feb 15, 2005
    Location:
    Swansea, South Wales
    #1
    We have just had a new MacPro with 500Gb HD installed. But, usable space is only about 450Gb. I know that formatting requires space but 50Gb?:mad:

    We have the same problem with a 200Gb MacBook Pro.

    I feel like I have just bought a new car and found it has no steering wheel.
    :confused:
     
  2. zero2dash macrumors 6502a

    zero2dash

    Joined:
    Jul 6, 2006
    Location:
    Fenton, MO
    #2
    I have a 320g Seagate.
    If the drive is empty - it registers as 298g.

    It's the way hard drives are. :eek:
    Chalk it up to that + the OS/app installation space taken up.
     
  3. balamw Moderator

    balamw

    Staff Member

    Joined:
    Aug 16, 2005
    Location:
    New England
    #3
    http://en.wikipedia.org/wiki/GiB

    long standing issue with HDD vendors, they quote capacity in gigabytes, but the OS reports gibibytes which give you automatically a 8% reduction in space.

    a 500 GB drive only has 465.6 GiB, which is usually what the OS reports.

    500*1000*1000*1000 = 465.6*1024*1024*1024.

    B
     
  4. G.Kirby thread starter macrumors regular

    G.Kirby

    Joined:
    Feb 15, 2005
    Location:
    Swansea, South Wales
    #4
    Just been doing some maths. Looks like there is a consistent ratio to the size of HD and the amount of space after formatting. The magic number looks to be a ratio of 1.074.

    So if you want to know how big a HD will be when formatted do this bit of maths.

    Proposed HD size (eg 500Gb)
    Divided by 1.074
    Gives you your usable HD size (465.5Gb)

    :eek:
     
  5. G.Kirby thread starter macrumors regular

    G.Kirby

    Joined:
    Feb 15, 2005
    Location:
    Swansea, South Wales
    #5
    Thanks, I think:confused: That's some proper Maths there lol:D
     
  6. balamw Moderator

    balamw

    Staff Member

    Joined:
    Aug 16, 2005
    Location:
    New England
    #6
    1.0737=1.024*1.024*1.024 (see the article I linked above).

    B
     

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