Greendrive not compatible with USB 3.0?

Discussion in 'Mac Accessories' started by davidra, Jan 19, 2013.

  1. davidra macrumors 6502

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    Oct 12, 2011
    #1
    I ordered this drive:

    http://www.buy.com/pr/product.aspx?sku=243030713

    1.5 TB, said to be USB 3 compatible on the order page. Drive arrived today and on the box it says under OS support: Mac OS X 10.5 or later (USB 2.0 speed). The manual inside says : "As of this printing, there are no USB 3.0 host bus adapters with Macintosh hardware support. The GreenDrive3 is fully supported with Macintosh based computers via USB 2.0 connections".

    I haven't unboxed the thing yet because if it won't do USB 3.0 on my pending iMac (which shipped today) I will be returning the drive. I'm hoping this was printed some time ago and now the drive will be USB 3 compatible with an iMac. Anyone else seen this, or know the answer? I've sent a ticket to the manufacturer but who knows how long that will take....and if it's not compatible I want to order one that is.
     
  2. davidra thread starter macrumors 6502

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    Oct 12, 2011
  3. simsaladimbamba

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    #3
    The drive is from 2011, USB 3.0 was supported by Intel's chipset in 2012, thus the first Macs with USB 3.0 arrived in 2012.

    As it is a drive like any other, depending on the controller, it will probably work as USB 3.0 drive. What happens if you test it? Can you not return it once it has been opened?
     
  4. davidra thread starter macrumors 6502

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    Oct 12, 2011
    #4
    I could....just wanted to return it quickly if it doesn't work so I would have a backup drive. What's the best way to test the speed?
     
  5. simsaladimbamba

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    #5
    You can use the following applications to benchmark the speed of your HD:
     
  6. davidra thread starter macrumors 6502

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    #6
    i got the following:
    On Xbench: Sequential uncached write 148 MB/s (4K blocks)
    120 MB/s (256 K blocks)
    uncached read: 23 MB/S 4 K blocks
    132 MB/s (256 K blocks)

    On BlackMagic:

    Generally reading around 120 MB/s, same for writing.

    Are these speeds USB 2 or 3?? I had thought USB 3 was GB/s??
     
  7. simsaladimbamba

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    #7
    Those are the correct speeds, as they are limited by the HDD speed. And USB 3.0 is limited to 5.0 Gb/s (1 B(yte) = 8 b(it)), theoretically. The practical speeds are much lower, around 3.2 Gb/s or so, but those only work with SSDs anyway.

    HDDs have a speed limit of 120 to 145 MB/s, many are even lower depending on their size (2.5" or 3.5"), capacity and rotational speeds.

    USB 2.0 can go up to 37/38 MB/s.
     
  8. davidra thread starter macrumors 6502

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    Oct 12, 2011
    #8
    Excellent, thank you so much. I assume I should hold onto the drive then. I also noticed the Random as opposed to sequential are much lower with 4 K blocks: 1.08 MB/s write and .71 MB/s read but higher in the 256 K blocks (69 and 32 MB/s). Is this also normal behavior? Thanks again....newbies appreciate the assistance.
     
  9. simsaladimbamba

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    #9
    They are normal.
     
  10. davidra thread starter macrumors 6502

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