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What can I do to optimise the data transfer speed from an external USB 3.0 docking? I have two HDDs inserted into the docking device, and I have it connected via only USB 3.0 on my laptop (blue colored one). I get rsync speeds of 50MB/s but I am not sure if this is the maximum speed I can get and how I could tweak it to optimal speed.

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Experiment using different USB ports. Not all ports/controllers are equal and you might be surprised at the different speeds between two ports. – adempewolff Jun 3 '12 at 10:27
Can you find your docking in this list: sudo lsusb -v | grep bcdUSB -C5? Please add the output for your docking to the question. – jippie Jun 3 '12 at 10:34
Are your drives SSD? – Mitch Jun 3 '12 at 10:37
Your speed are limited to your HDD speed , unless you're running on SSD drives , but that's not fast enough as well – warl0ck Jun 3 '12 at 13:19
Dual-drive docks can be slow -- 50 MB/s is fine if you're copying from one docked drive to the other. – izx Jun 3 '12 at 13:46
up vote 2 down vote accepted

You should remember that the data is transferred to the destination, only as fast it is being read off the source.

USB 2.0 has a maximum theoretical speed limit of 60 MB/s. Actually, it is only today, 8 years after the launch of USB 2, that USB 2 devices are able to fully exploit this speed. Most of the USB 2 devices today max out at 30-35 MB/s. The reason for this, the read-write speeds of devices bottlenecks the transfer process.

Of course USB 3.0 isn't all about speed. The new bus specification is also intended to accommodate the next generation of power hungry devices, gadgets and drives.

So for USB 3, don't expect speeds of 400 MB/s plus; even though the data could be transferred at that rate, it cannot be read off the source HDD or written to the external drive at the same rate. Now if you were to hook up a superfast SSD to the dock, & also had a similar speed SSD in your system, then the transfer process would be definitely faster, since both drives could read & write lighteningly fast. So it is more likely that the transfers you are doing are bottlenecked by the storage drives, in particularl, their sequential read/write speeds; not due to the fault of USB 3.

Source: tomshardware

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