Connect 2 Macs via Thunderbolt

Discussion in 'Mac mini' started by YinZhouWang, Aug 9, 2011.

  1. macrumors newbie

    Aug 2, 2011
    Today my Thunderbolt cable finally arrived. So I connected my MM with my MBA (target drive mode). I moved over some fairly big files, but was surprised due to the slow data transfer. For one GB it needed 30 seconds! I can match that with my old USB drives.

    Is there something I'm missing?
  2. macrumors 6502

    Nov 21, 2007
    The base model only has a 5400RPM HDD. The write speed should be around 30MiB/s. Read speed should be higher.
  3. thread starter macrumors newbie

    Aug 2, 2011
    The MM as well as the MBA have SSDs.
  4. macrumors 6502


    Mar 7, 2009
    The MM has an SSD as an option. not standard like the MBA
  5. macrumors 603


    Apr 13, 2010
    this is due to software limitations. there are reviews that mac to mac is slow with t-bolt connections no one has posted speeds of any worth while note. one of your computers is a target disc and that software limits speed. it will be under fw800. I will look for link. found the story
  6. thread starter macrumors newbie

    Aug 2, 2011
    Thanks for the link.

    I don't want to start ranting, but what the hell?! I hope this is just a bug, otherwise I spent 6000 bucks for my hardware renewel for nothing.
    Apple throws a promising product on the market, advertising it as the new speed revolution and what do I get? Half-assed technology that cannot compete with an 8 year old product.
  7. macrumors 6502


    Sep 21, 2005
    Reject Beach
    Perhaps this is a stupid question, but I don't own a Thunderbolt-equipped Mac. Is it possible to establish a network connection over the Thunderbolt port, like you can with FireWire? Is it possible that directing the traffic through the network stack might get around the speed limitation imposed by TDM (not sure what it uses to communicate)?
  8. thread starter macrumors newbie

    Aug 2, 2011

    As far as I know (and tried), no. At least not yet. I think, it's just a software limitation to be resolved.
    Looking at the hardware specs, it should be possible.
  9. macrumors 6502


    Mar 7, 2009
    The new TB Cinema display does have a Ethernet Adapter built into it.
  10. thread starter macrumors newbie

    Aug 2, 2011
    So? phairphan asked about connecting two Macs via Thunderbolt. What does Ethernet have to do with it?
  11. macrumors 6502


    Mar 7, 2009
    "Is it possible to establish a network connection over the Thunderbolt port" Last i checked Ethernet was a viable network connection
  12. macrumors 6502


    Jan 5, 2010
    Washington, US
    Thunderbolt was not designed to do Mac to Mac connection, it can but that isn't it's primary function.

    Target disk mode hasn't been updated yet because they haven't had time yet. It's an old technology, they probably didn't think about updating it when thunderbolt came out because they were so busy deploying other products alongside it.

    Give them a chance.

    You could try being productive by writing an email or reporting a bug.... Complaining here won't help you.
  13. thread starter macrumors newbie

    Aug 2, 2011
    I just expressed my disappointment. And believe me, I already sent them an email. Which most certainly won't speed up the process, but anyways.
    I've been a Mac user for 18 years, so don't worry about giving Apple a chance. ;)

    Basically you're right. However what I think he meant, is establishing a network connection with the advantages of Thunderbolt technology:
    take a TB cable, plug it into two computers -> start a network. Like Firewire does. With an ethernet connection you're limited to 1g throughput.
  14. macrumors 6502


    Mar 7, 2009
    Well fFireWire does top out at 800 Mbits. If the Ethernet on the TB cinema display has Gigabit Ethernet, a cross-over cable should possibly provide for faster transfers. After factoring in Protocol, and error correction ETC ETC.

    Granted i'm sure two TB Cinema displays just to transfer some files is over kill. I'm sure its only a matter of time before you see dedicated TB network adapters. I understand the the spirit of the question. But this does provide a solution to the literal question.
  15. dyn
    macrumors 68000

    Aug 8, 2009
    And nobody even thinks about the data that they are transferring... That alone renders all the reports completely useless. The kind of data has a huge impact on transfer speeds no matter what kind of connection you use. It is therefore crucial to account for this but nobody has done so. The mentioned speeds are only for sequential filetransfer with very big files. Think of single 4GB files, not those 8 MB jpg files. If you look at random read/write speeds which is important for small files things become completely different. SSD's have a much slower speed in this area than the advertised sequential speed.

    You need to take the info on that link with a very big box of salt. They are very simplistic results that *may* show that target disk mode will not go beyond fw800 speeds. It also may just be the data that is causing it.
  16. macrumors member

    Aug 23, 2011
    Just for the record, crossover cables aren't necessary since like the G5 (I think). I turned my old G5 into a Mac OS X Server... and have it linked to my late 2009 iMac with a normal old ethernet cable.... no hub or switch in between.

    Looking forward to upgrading though and would love to be able to daisy chain a new iMac, MM (used as server) and pegasus raid with just two Thunderbolt cables.
  17. macrumors 65816

    Aug 24, 2011
    I can confirm cross over cables are not necessary for Mac to Mac connections. Gigabit is fast, but not much faster than FW800.
  18. Nicholas Savage, Oct 19, 2013
    Last edited: Oct 19, 2013

    macrumors newbie

    Oct 19, 2013
    Southern Wisconsin

    Eyah. The rumor is that IP networking over thunderbolt will be added to 10.9. Assuming no soft limitations it should / could be a very fast way of linking two TB equipped machines together. Asus was supposed to ship a thunderbolt-pcie host adaptor at a 200$ish price range. Never actually went into full production. TB to TB networking could be pretty fast. After taking out signal overhead it is around 1GB a second up/down. Even on a pc, 2 200$ cards for what is essentially a crossover link at that speed is. . . .appealing.

    In regard to shortcut3d's comment. I forget the exact name. Automatic MDI or MDIX or some has been standard on everything with 1000BASE-T. So it has been around for a while. As for FW800? You might get rates up in the 60-70 range; up near 80 if you are lucky; but with gigabit and AFP it isn't unreasonable to move data up around 100-110MB/s when you don't have a crappy switch. More if you are running LACP on a mac pro.

    *EDIT* Bah, just realized this was an ancient thread.

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