When using Migration Assistant to move users, files, and folders from an old Mac to a new one, you have a few different choices, depending on the Macs involved. Presuming that both Macs have appropriate ports, which ports should be used in a real-world situation? Please do not provide quotations of theoretical port speeds; I'm looking for real-world experiences as to what will get the job done faster.

Port choices:

  • FireWire 400 in target disk mode
  • FireWire 400 to 800 in target disk mode
  • FireWire 800 in target disk mode
  • 100 Megabit Ethernet to Gigabit Ethernet in the OS
  • Gigabit Ethernet to Gigabit Ethernet in the OS
  • Thunderbolt cable in target disk mode
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    Rolled back the edit because I'm specifically asking about data transfer rates in the Migration Assistant scenario, not in a general sense. For example, Thunderbolt and Fiber Channel are both fast data transfer technologies that have been implemented on Macs, but neither is appropriate for Migration Assistant use, putting them in the same boat as USB 2.0, USB 3.0, and eSATA. – Negrino Mar 17 '11 at 9:22
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    Sadly, this question is rethorical. There's no need to obtain "real-world experiences" that won't match the theory. The thing is that each port is faster than the other, so just put them in order: Gigabit > Megabit > FW800 > FW400. So if you can connect both machines to a gigabit switch, it will obviously be faster. – Martin Marconcini Mar 17 '11 at 9:49
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    @Martín Nothing rhetorical about it. My experience is that theoretical speeds for a given technology often do not measure up to real-world speeds. For example, USB 2.0 is specified at 480 Mbps, versus FireWire 400's 400 Mbps. Yet you can easily find many benchmarks showing that FW400 is quite a bit faster than USB 2.0 in actual use. There are other considerations in the Migration Assistant scenario, such as copying as many as 2 million small files, that demonstrate the strengths/weaknesses of a particular technology in terms of overhead and signalling. – Negrino Mar 17 '11 at 23:07
  • @Negrino although you're correct, I still insist that the advantages of Gigabit over 100Megabit Eth (or 10!) and FW800 over 400 (and USB 1/2) is very obvious. You're right tho' that FW400 can sustain better throughput, but a clean USB2.0 bus is "faster" than FW400 in some scenarios (small files, as you correctly described, versus a huge file, where FW400 will maintain better overall speed -> tested by me). – Martin Marconcini Mar 18 '11 at 10:12
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    This question can't be answered decisively since so much depends on the actual situation on the mac providing the data. FW800 is generally slightly faster than Gigabit ethernet for sustained data transfers due to the lower overhead and latency. Connecting the two macs with a single cable will reduce network effects, but the major factor in running migration assistant is how fragmented the directory catalog is and not whether FW800 or GBE is used for connection. 100 ethernet is the slowest followed closely by FW400. – bmike Apr 15 '11 at 3:18

Gigabit ethernet to gigabit ethernet. Next would be FireWire 800 to FireWire 800. Thunderbolt target disk mode is testing to be equivalent to FireWire 800 in target disk mode.

It looks like the OS can keep a gigabit link fuller than target disk mode is able, even when the target mode link has vastly higher bandwidth available.

  • I'd say that Megabit would be able to sustain a better transfer rate than FW800. But I don't have anything to back that up. – Martin Marconcini Mar 17 '11 at 9:49
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    @Martín: Technically, FW800 can support 3.2 Gb connections, but ethernet is faster in real-world use. Also, there is no Mb ethernet. The first ethernet specification was 10 Mb, followed by 100 Mb and Gb. FW400 supports 400 Mb connections, but I don't know what it gets in the real world. – ughoavgfhw Mar 17 '11 at 19:48
  • you're right! – Martin Marconcini Mar 17 '11 at 19:52
  • I edited the question to reflect your correction regarding 100Mbps Ethernet. Thanks. That will teach me to write questions late at night! – Negrino Mar 17 '11 at 23:11
  • This answer is outdated... the fastest now I've been able to test is a smb mount over thunderbolt bridge (near 10 Gigabit). It's faster that thunderbolt target disk mode. Tested on USB-C macbooks (2018) – Josh Hibschman Dec 6 '18 at 21:37

While the prevailing thinking that gigabit is faster than FW800 is true in the most rudimentary theory it doesn't hold up in practice. When migrating over Ethernet the source machine has the OS loaded, and is communicating over a chatty protocol designed for the wild unknown that is an open network.

Firewire transfers with migration assistant are performed with the source machine in "target disk" mode... no OS is loaded, and it's essentially functioning as an external hard drive.

In my experience FW800 in target disk mode provides superior performance.


I just transferred a 25GB user from a MacBook Pro 5,3 running 10.7.5 to a MacBook Pro 9,2 via Gigabit Ethernet (direct cable connection with self assigned IP addresses). It took 23 minutes although the time-remaining indicator going from 5 to 8 then dropping to zero for most of that time.

I then transferred that same user from the MacBook Pro 9,2 in target disk mode to a MacBook Air 4,2 running 10.7.5 via a Thunderbolt and it took only 5 minutes with the time-remaining indicator dropping monotonically from 3 to 0.

I conclude that Thunderbolt is much faster than Gigabit Ethernet.


Last time I updated my computer I tried over FireWire 400. It said 23 hours, I cancelled it after four. I plugged in ethernet and the whole process took 23 minutes. Ethernet - Ethernet is faster than FireWire 400.

  • Gigabit Ethernet surely is, 100 Megabit probably not – nohillside Nov 29 '12 at 21:23

Kinda depends on the drives involved. My migrations (I do these for all my family for every new Mac) go fastest through Thunderbolt when both ends are using Flash Storage, but have seemed to go faster by Gigabit Ethernet when its a Hard Drive to Flash Storage, and if it's Hard Drive to Hard Drive, I can't tell the difference between Gigabit Ethernet and Firewire 800.

Target disk mode is my go to for Mac to Mac migrations, the time I remember clocking it, I transferred 120gb from my MacBook Air 2011 to 2013 about 5 minutes faster when I did it Target Disk mode than when I redid it OS to OS.

Why I had to redo it, well, we don't talk about that ;) but it was a good opportunity to benchmark :)

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