Do I have SATA III/II...Explained

Discussion in 'MacBook Pro' started by CosmoPilot, Jun 28, 2012.

  1. CosmoPilot macrumors 65816


    Nov 8, 2010
    South Carolina
    I've seen a lot of questions concerning SATA III (II), and what Mac has what. This little tutorial should help you determine what you have in the HD Bay as well as the Optibay. Mods, if this info is somewhere else, please move as appropriate with my apologies.

    Step 1. Click on the Apple logo and select "About This Mac"
    Step 2. Click "More Info"
    Step 3. Click "System Report"
    Step 4. In the left panel, highlight "Serial-ATA"
    Step 5. Select the controller with the triangle next to it (see pic below)

    Now look at the Link Speed. If 6 Gigabit is displayed you have SATA III. If 3 Gigabit it's SATA II.

    The "Negotiated Link Speed" is what connection you currently have. In the picture provided, you can see the Link Speed is 6 Gigabit while the Negotiated Speed is 1.5. What this means, is the DVD drive is standard SATA. Therefore, while the controller is SATA III (link speed), it can only achieve a negotiated link speed of 1.5 because the DVD limits it. If a SATA III SSD were installed in place of the DVD (Obtibay), the negotiated link speed would change to 6 gigabit.

    I hope this helps alleviate some confusion.

    Attached Files:

  2. SR71 macrumors 68000

    Jan 12, 2011
    Boston, MA
    Great thread! Answers some questions I had and will definitely also help others who were confused by this!
  3. ZipZap macrumors 603

    Dec 14, 2007

    6G transfer rate = SATA III
    3G transfer rate = SATA II

    USB 3 up to 5G
    TB up to 10G
  4. TickleMeElmo macrumors regular

    Jun 19, 2012
    There is overhead to consider.

    6Gbps = 750MBps, in real life you won't see more than 600MBps though.
    3Gbps = 375MBps, last generation drives topped out at or below 300MBps.

    Realistic USB3 performance is less than 450MBps (there are so walkarounds with turbo mode etc. but they come at a cost).

    Thunderbolt more or less reroutes PCI Express lanes along with thunderbolt. Not sure what the actual overhead is one that (whether it is PCI Express 2 or 3 makes a big difference).
  5. Bholifield49012 macrumors newbie

    Jun 23, 2012
    Great thread..I wish I would have seen this a few months ago. I purchased a Kingston HyperX SSD(Sata III) for my mid 2010 Mac Mini(Sata II). I was very excited about getting close to 500 mbps read and write and ended up with only 170mbps write and 250mbps read. It is still very very very fast when opening programs but my new Retina Macbook Pro is kicking everything's ass.:D
  6. CosmoPilot thread starter macrumors 65816


    Nov 8, 2010
    South Carolina
    Well, the good thing with the non-retina MBPs is you can always take the SSD with you when you part company!

    I imagine the rMBP is a killer machine!

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