Transfer between external hard drives extremely slow.

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Level 1

8 points

Transfer between external hard drives extremely slow.

I've been transferring data between my hard drives for a couple hours now and it's barely at 100 GB. Both externals are brand new practically so it's not a bad drive. I'm comparing to experience here so I know the hard drive can handle speeds of up to 100MB/s. This is how fast I originally transferred the data to my first hard drive from my Macbook. However, it seems like the transfer rate between external to external is massively slower. Is there a workaround for this? I was thinking of transferring it to my computer first and then transferring it to the other drive. That would also take a long time though. Any ideas?

MacBook Pro 15", 10.13

Posted on Jan 31, 2019 4:15 PM

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Answer 1

Best reply

Grant Bennet-Alder

Level 10

127,567 points

Jan 31, 2019 5:05 PM in response to Earofcorn

 Menu > about this Mac > (System Report) > USB

Look at the two ports involved and check their speeds. One may be "stuck" at USB-2 speed.

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100M Bytes/sec is VERY speedy for a rotating magnetic drive. That could be the speed of the first burst. Typical speeds are half that user ideal conditions.

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Answer 2

Earofcorn Author

Level 1

8 points

Jan 31, 2019 4:42 PM in response to Lanny

https://www.google.com/search?q=macbook+pro+2013+usb+ports&oq=macbook+pro+2013+usb+ports&aqs=chrome..69i57j0l5.5720j0j7&sourceid=chrome&ie=UTF-8

says I've got these

Two Thunderbolt ports (up to 10 Gbps)
Two USB 3 ports (up to 5 Gbps)

I'm using my USB ports for the transfer

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Answer 3

Earofcorn Author

Level 1

8 points

Jan 31, 2019 5:20 PM in response to Grant Bennet-Alder

I think I just figured out what was going on. That really helped. It made it clear what was happening. I had my laptop fan connected to one usb port and the fan usb is a hub with a USB connector. I had one external plugged into that hub, through the fan's usb hub, which apparently maxes out at 12mb/s. I took out the fan and it's working great now. Thanks a lot.

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