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maximit

macrumors member
Original poster
Apr 20, 2009
80
52
I bought a multiport adapter and had a problem with My Book Duo USB. Reading was fine at 120+ MB/s but writing would top out at 30 MB/s and the connection would drop out constantly, not being able to complete a Time Machine backup.

The solution was to get a Belkin USB-C to USB Micro B cable and connect directly to one of the port on the MacBook Pro. Seems the Multiport adapter does not play nice with external USB hard drives. So if you are having problem with an external drive, pick up a direct cable from USB-C to whatever port your drive uses (USB-A, USB-B, USB Micro etc).
 
I bought a multiport adapter and had a problem with My Book Duo USB. Reading was fine at 120+ MB/s but writing would top out at 30 MB/s and the connection would drop out constantly, not being able to complete a Time Machine backup.

The solution was to get a Belkin USB-C to USB Micro B cable and connect directly to one of the port on the MacBook Pro. Seems the Multiport adapter does not play nice with external USB hard drives. So if you are having problem with an external drive, pick up a direct cable from USB-C to whatever port your drive uses (USB-A, USB-B, USB Micro etc).
If I'm not mistaken, the multiport is relegated to usb 2.0. You need 3.0 for decent transfer speeds. I don't think the multiport is meant for transferring, or at least not large amounts of data. A usb-a 3.0 cable will get you up to 120 MB/s read/write.
 
The multiport is a USB 3.0 port as per Apple. The connection was USB 3.0 to the drive, confirmed in System Report, and even though it did get 120 MB/s READ speeds it only got 30 MB/s WRITE and the connection was extremely unstable, periodically dropping connection, unmounting drive etc. From the reviews on Apple.com it seems a lot of people are having similar issues with external drives. Just wanted to post a solution for anyone encountering the same problem.
 
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You're solution is good for getting maximum speeds and I would recommend the same but of course you'll quickly run out of ports. The next best option is a decent USB-C to USB-A hub. I use this one. It's robust enough that I have piped through it an, a external USB SSD that still gets to close its max at around 450 MB/s read/writes and another USB 3.0 hub for an ethernet adapter, keyboards etc.
 
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Here are some tests I ran yesterday, connected via the mulitport adapter and a 10 port usb 3 hub, ymmv:

2016 13" Macbook Pro 2.0 Intel Core i5-6360U @ 2.0 GHz (2 cores) - stock version

LaCie Rugged 500GB: R: 37.4 / W: 39.2
OWC Envoy 500GB: R: 279.8 / W: 209.4
Transcend 256GB R: 414 / W: 300.5
Internal 256GB : R: 2000 (max) / W: 1317.5
 
Speed was not my main concern as its a backup drive. I was frustrated the drive would not stay connected and would fail to copy large files. Like apple says, some USB 3.0 drives are not compatible with the multiport adapter. Thankfully the WD My Book Duo has a built in hub with two USB-A 3.0 ports so I did not run out of ports, but I do have a second cable to plug in addition to the multiport adapter. With just two cables I have my setup covered:

MacBook Pro 2016
USB-C Multiport Adapter
61w charger into multiport
WD Drive (USB-C to Micro B cable)
Aluminum Cinema 23" DVI Display (connected via DVI to HDMI adapter to Multiport. Display USB connection to WD drive, has a hub with two more USB 2.0 ports)
Apple wired Keyboard (into the Cinema)
Printer (into the Cinema)
Apple Superdrive (direct to multiport as it won't work though a hub)
Drive dock/Duplicator USB 3.0 (into the WD drive)
 
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Was the drive in question bus powered, or did it have its own power supply?
 
The multiport is a USB 3.0 port as per Apple. The connection was USB 3.0 to the drive, confirmed in System Report, and even though it did get 120 MB/s READ speeds it only got 30 MB/s WRITE and the connection was extremely unstable, periodically dropping connection, unmounting drive etc. From the reviews on Apple.com it seems a lot of people are having similar issues with external drives. Just wanted to post a solution for anyone encountering the same problem.
Ouch, I stand corrected and thoroughly humbled on the 3.0 thing. Interweb is full of conflicting information. On a side note, curious as to why Apple doesn't clearly show this on their specs page or make the adapter blue like most other usb 3.0 ports.
 
Anyone get a full time machine backup (200+ GB working via a USB-C adapter)? I've tried a couple different adapters and always get a kernel panic after about 100GB.
 
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