USB2 speed with a Lacie thunderbolt little big disk

Discussion in 'MacBook Pro' started by fredbergy, Mar 17, 2013.

  1. fredbergy macrumors newbie

    Mar 17, 2013
    Hi all!

    I'm pretty new in mac world have my mbp for about a year now.

    As i say i bought my lacie thunderbolt about 6 month ago and everything have been fine with it. My transfer rate was awesome as it supposed to be. (about 120Mb/sec approx 9-10sec for a 1Gb file)

    As i use my thunderbolt for work i bought a WD element HDD USB3 HDD for backup purpose.

    I plugged it and find that instead of usb3 speed it gaved a usb2 speed (my mbp have AppleUSBEHCI driver...). I was thinking it will be usb3 speed?? (Can my mbp deliver usb3 transfer rate??)

    Anyway it is for backup purpose so it's not a big issue with this HD..

    The first time i plugged my lacie thunderbolt after that i plugged my WD HDD i get usb2 transfer rate (about 40Mb/sec transfer rate) with my lacie.

    Took me about 5min to transfer a 10Gb file in it... These where 16 folder with 24 audio track in each folder..

    I tried to reboot my mbp and the same thing happen, tried to change the thunderbolt port on my Lacie without success (anyway i think both are in/out)

    I make another test to transfert from my mbp a folder with 12 .avi episode in it the folder was 4.47Gb and took me about a minute to transfert so pretty much faster then my transfer with my audio track...

    Do we have a problem here??? Or it's a normal transfer rate considering the large amount of file being transfer? (16X 24 files)

    Thanks a lot for your help!

  2. twdi macrumors member

    Dec 21, 2012
    I will follow this thread because I need external storage for my new rMBP.
    I was thinking to buy a g-drive 3Tb (usb3) for 250 euro instead of 440 for 2Tb Lacie thunderbolt...
  3. hfg macrumors 68040


    Dec 1, 2006
    Cedar Rapids, IA. USA
    Your LaCie Thunderbolt "Little Big Disk" is actually 2 disks inside running as a RAID-0 array for speed. They also use fast disks to further improve performance.

    Your WD portable USB 3 disk will not run at USB 3 speeds, it will run at the maximum transfer of the single hard disk contained within, which is considerably slower than the maximum USB 3 (or Thunderbolt) transfer rates. Most single disk portable drives don't even push USB 2 limits.

    If you had a fast SSD drive, it might be limited by USB 3 if it is a premium SSD. Running a pair of SSDs in RAID-0 in the LaCie enclosure would require the Thunderbolt interface to avoid limiting data transfer rates, but that would not approach the maximum data rate for the Thunderbolt interface.

    It's sort of like a super-highway where the speed limit is 120mph, but your little Vespa can't do more than 30mph, even with a tailwind. :)
  4. g4cube macrumors 6502a

    Apr 22, 2003
    Also, when you copy from one drive to the other, the speed you see will be that of the slowest drive.

    Benchmark tests like Black Magic or AJA measure performance by writing a pattern from RAM to the drive and then read it back into RAM, so you only see the speed of the drive under test.
  5. simsaladimbamba

    Nov 28, 2010
    USB 2.0 is capped of at about 37 to 38 MB/s with modern x86 based Macs, most 5,400 RPM HDDs are much faster than that, unless I am misunderstanding your "single disk portable drives" for something else.
  6. snaky69 macrumors 603

    Mar 14, 2008
    If you've had your MBP for about a year now, either you have a late 2011 or an early 2012. If yours is a 2011 model, it does not support USB3.

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