Hard drive speeds and Thunderbolt

Discussion in 'iMac' started by AppleFan360, May 1, 2012.

  1. macrumors 68000

    Joined:
    Jan 26, 2008
    #1
    The other day I purchased a Western Digital Thunderbolt DUO drive and did some speed tests and this is what I came up with.

    The Thunderbolt drive gets about 103 MB/s on read and write in RAID 1 (mirroring) Haven't tried RAID 0 which I assume would be faster.

    My other Firewire 800 drive gets about 65 MB/s read and write.

    The internal hard drive on my Mid 2011 iMac (i5 2.7) gets about 98 MB/s.

    Do these numbers sound correct? Shouldn't the Thunderbolt drive be getting more speed? I was expecting at least 150 MB/s or more. I'm thinking maybe it's because I have it in RAID 1.

    I was also concerned about the internal hard drive on my iMac. Is that really as fast as that hard drive can perform?

    Thanks.
     
  2. macrumors G5

    Macman45

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    #2
    Sounds about right...In RAID0 the claim is 120MBS...I am awaiting delivery of a PegasusR4 which will be using a thunderbolt cable attached to my iMac. A lot depends on the speed of your HDD, but from the reading I've done lately I'd say your figures are in the right place with that setup.

    I already have a 3TB Time Capsule taking care of 3 Macs, so I;m going for real time speed with the Pegasus...Should be interesting..:)
     
  3. macrumors newbie

    BlueFinch

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    #3

    If you really want more speed, you have to use a Solid State Drive. Thunderbolt can't boost a Hard Disc drive. It's like a Beetle Motor in an Porsche.

    Your numbers are correct.
     
  4. simsaladimbamba

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    #4
    As the HDDs used in that WD Thunderbolt Duo enclosure probably have only a maximum speed of 105 to 120 MB/s, your speed sounds about right.
    Just because Thunderbolt does allow fast transfers, doesn't mean HDDs will be faster than they currently are.
    If one of those tow WD HDDs would be inside your iMac, it would probably also get about 100 to 105 MB/s.
     
  5. Itzmemark, May 1, 2012
    Last edited: May 1, 2012

    macrumors member

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    #5
    So are you saying to get the smaller ssd inside the imaand have a thunderbolt hd for more space?
     
  6. thread starter macrumors 68000

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    Jan 26, 2008
    #6
    That's what I thought. Kind of a let down in a way. I was thinking maybe the hard drives would perform better with a bigger pipe. What I do find interesting is that the external drive is now faster than the internal drive. Something I thought I would never see with all my years of using external drives.
     
  7. macrumors 604

    theSeb

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    #7
    The pipe is not the problem. The hard drive speed is. If you put in faster hard drives, then it will be faster. If the hard drive can only read and write at a certain speed, it cannot do it any faster no matter how fast the pipe is. A mechanical hard drive is not faster when connected via SATA III versus SATA II. This is because it cannot saturate the SATA II link. Therefore giving it a SATA III or a Thunderbolt connection won't make it magically faster. Imagine a car with a max speed of 120 MPH. Imagine that it can reach this speed on a level road in 2 miles. If I make the track 4 miles or 6 miles or 20 miles, it will still only go up to 120 MPH.

    However, RAID 1 is quite a lot slower than no RAID or RAID 0, so try RAID 0. It's faster, but obviously the risk of losing your data is large. If either one of the drives fail, then you will lose your data. In RAID 1 if one of the drives fail, you can still get your data back.
     
  8. macrumors G5

    Macman45

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    #8
    Which begs the question....What HDD's can I expect to be installed in my R4? I'm not going to be a happy bunny if after shelling out all that cash I end up with anything less than top end 7200 drives in there. Having said that, I can't see them doing it, not at the retail price of £849.00 (It's going right back if they do)
     
  9. macrumors 604

    theSeb

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    #9
    It comes with 7200 RPM drives. The reviews I've read mention that they got units with Hitachi Deskstar 7K3000 HDDs. That may change, but they will definitely be 7200 RPM.
     
  10. thread starter macrumors 68000

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    #10
  11. macrumors G5

    Macman45

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  12. thread starter macrumors 68000

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    #12
    No, I wasn't expecting magically faster, just a bit faster since the drive can now perform as fast as it can given the interface it's working through.
     
  13. macrumors G5

    Macman45

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    #13
    I think 120MBS is pretty much flat out....I will test mine in various configurations when I get the unit...(30th May) but if I can achieve that speed consistently I will be happy.
     
  14. macrumors 604

    theSeb

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    #14
    How did you check what speeds you're getting? Why don't you run the disk tests from xbench and post the results?
     
  15. macrumors newbie

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    Aug 19, 2003
    #15
    I have the 12 TB Pegasus R6 and I'm getting 500+ MB/s on both read and write with 6 drives in RAID5. The R4 might be a bit slower, but I doubt you will be disappointed. :)
     
  16. macrumors member

    Joined:
    Mar 18, 2012
    #16
    I Have a Seagate Desktop GoFlex Thunderbolt.

    Using Blackmagic Disk Speed test I get about 128 MB/s read and 138 MB/s write. This unit has a single Seagate 3TB drive attached - I don't know it's specs.

    If I plug an ordinary 3.5 inch 1 TB drive onto the same adapter I get 94 MB/s read and 93 MB/s write - this is an older bare drive.
     
  17. macrumors 6502

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    Jan 5, 2012
    #17
    Is that the 3 platter or 4 platter 3TB Seagate drive? I am curious to know how the 1TB/disk Seagates perform under Thunderbolt.
     
  18. macrumors 6502

    mzjin

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    #18
    Thunderbolt storage solutions are only useful with SSDs. Otherwise, mechanical HDs can't read/write fast enough to saturate TB.
     
  19. thread starter macrumors 68000

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    Jan 26, 2008
    #19
    Well, I repaired the permissions on my iMac and managed to get a little speed increase.

    The WD Thunderbolt Duo is now reading a writing at 113 MB/S.

    The internal iMac drive is now at 104 MB/S.

    I'm using Blackmagic Disc Speed test.
     
  20. rw3
    macrumors 6502a

    rw3

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    #20
    You are in RAID1....that is where the slowness comes from. Each drive is having to right the same data so it will be slower.

    My LaCie 2big Thunderbolt Series 6TB (2x 3TB 7200RPM HDDs) in RAID0 gets 340MB/s on Read & Write. I never tested in RAID1 but I wouldn't expect anything over 150MB/s.

    So to answer your question: RAID1 will always be slower than the rated specs of a manufacturer because their claims are made in RAID0....

    Also, the Western Digital Thunderbolt Duo uses Western Digital Green HDDs meaning 5400rpm and slower overal performance.
     
  21. macrumors 68040

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    #21
    Correct. If you get the 4TB R4, it will come with 4 1TB SATA2 drives. The 8TB R4 comes with 4 2TB SATA3 drives. I do not know how much difference the SATA2/3 difference will make. My 8TB R4 is very fast. Testing it against my Aperture 3 library on the iMac internal HDD, vs having the same library on a Pegasus 8TB R4 is stunning.

    /Jim

    ----------

    You are making an error if you say the TB is not useful for HDDs. Saturating TB is not the objective. Even a single TB HDD will be about 1.5X the performance of a FW800 drive. For a RAID array, the difference is much greater. Whether or not TB has additional headroom is irrelevant. It adds value to HDDs as well.

    /Jim
     
  22. macrumors G5

    Macman45

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    #22
    I'm going for pure speed...Whatever configuration gives me that I will use, even if I use the unit in a non-RAID configuration, but boy will I be happy with anything close to 500MBS...that will enable me to edit music in real time...Something I couldn't do with my previous set-up...Will post when I have tested the new system..Thanks for all the information too!..:)
     
  23. macrumors 68030

    wonderspark

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    #23
    I have a Mac Pro, but data transfer speeds all work the same way. I submit my personal disk speed tests for reference:

    My original Apple/Hitachi 640GB HDD ran at about 105MB/second tops.
    Apple/Hitachi 1TB HDD got about 96MB/sec. on a different test, so given they're essentially the same disk family, I call them even. These are 7200rpm disks.

    Two of those 1TB Apple/Hitachi drives in RAID-0 gets 215MB/sec.
    Three of the 1TB Apple/Hitachi drives in RAID-0 gets 330MB/sec.

    Now, one single Hitachi 5K4000 4TB 5400rpm "coolspin" drive gets 129MB/second all by itself. Pretty good example of platter density.

    Next up are my two Crucial M4 256GB SSDs, which will give 237MB/sec write, 270MB/sec read via the ODD bay SATA connection.
    Same disk in internal slot runs at 230MB/sec write, 266MB/sec read.
    Same disk connected via eSATA or USB3.0 (PCI card) will do 168MB/sec write, 246MB/sec read.
    Then if I connect via PCI RAID card, the same drive will do 281MB/sec write, 456MB/sec read.

    Now to make things really interesting, I have an Areca RAID card that runs eight 2TB WD RE-4 HDD in RAID-6, so it's reading/writing to 8x disks at a time, and calculating parity data on them at the same time.
    816MB/sec write, 714MB/sec read.

    I put all eight in RAID-0 for some tests, and it got 1101MB/second. This is over two mini-SAS cables.

    Anyway, I hope this sheds some light on how much disk speeds can vary depending on the disk(s), the data cable(s) used, and the number that are reading/writing simultaneously via RAID levels.
     
  24. macrumors 68030

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    #24
    Thunderbolt drives are going to be limited by the speed of the drives, not thunderbolt. I.e., if you're seeing 100 megabytes/sec that's the drive slowing you down.

    At 10 gigabit per channel, thunderbolt drives won't saturate the bus until they're pushing 1 gigabyte per second or so, which is enterprise storage array territory.
     
  25. macrumors G5

    Macman45

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    #25

    Did a little more digging around last night...The Pegasus SHOULD achieve speeds in excess of 400MBPS when using 2 T'bolt cables...The drives installed are top quality 7200's (Probably Hitachi but subject to change) This will give me the ability to work on large projects in Real-time as I said. Prior to this I was using a four bay USB dock...Fine for storage, but as much use as a chocolate coffee pot for real work on the fly!..:) All the information here points to good things to come...I do wonder why the lead delivery times are so long on the R4 though...I ordered this over a month and a half ago, and it won't be delivered until May 30th....The larger 8 / 16 TB units are ex-stock, but that was way over the top for my needs, despite being offered a generous discount by my Apple representative. I guess it makes sense...Enterprise outfits are bound to go with the higher capacity. Thanks for the information..:)
     

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