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sguser

macrumors regular
Original poster
Aug 12, 2010
159
138
Just got my MacBook Pro 2016 today. Plugged in Samsung T3 SSD drive and was surprised by extremely slow transfer speed, around 30 MB/s. The T3 is connected using the USB-C cable that came with the Mac (the one that is used for charging).

The Samsung T3 SSD works just fine on another MacBook Pro 2012, showing 400+ MB/s speeds.

Any suggestions what could be causing such extremely slow read/write to external SSD on a brand new Mac?
 
Did you try another USB port see if its perhaps a specific port.
 
Did you use the left side USB-C ports? Only the left-side ports offer full-bandwidth Thunderbolt 3 performance
 
My only two gripes with my new machine are:

1) i keep hitting the touch bar by accident because I am used to resting my fingers on the function row when not typing

2) I am never quite sure what cable to buy and use and how to tell them apart. Two cables, each of which have USB-c connectors on both ends, can behave very differently.
 
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I understood that there were specific cables to get TB3 speeds but you guys are saying there are also cables that only support USB2 and then some that do USB3.1Gen2 and then the TB3 cables?? Thats a lot of cables to keep track of and will confuse many as it did the OP.
 
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I have got the same to problems. I keep hitting Esc accidentally, or Back in Safari. And cables...yeah, I'm not looking forward to buying all those cables. I was hopping I could use this type-a to type-c adapter, but looks like it is just another Chinese junk...

My only two gripes with my new machine are:

1) i keep hitting the touch bar by accident because I am used to resting my fingers on the function row when not typing

2) I am never quite sure what cable to buy and use and how to tell them apart. Two cables, each of which have USB-c connectors on both ends, can behave very differently.
 
I understood that there were specific cables to get TB3 speeds but you guys are saying there are also cables that only support USB2 and then some that do USB3.1Gen2 and then the TB3 cables?? Thats a lot of cables to keep track of and will confuse many as it did the OP.

No, it's even better, different options:
- Charging only (uncommon, but it's possible)
- USB 2.0
- USB 2.0 + display port alternate mode (uncommon, but it's possible)
- USB 3.1 Gen 1 = 5 Gbit/s, basically renamed USB 3.0
- USB 3.1 Gen 1 + display port alternate mode
- USB 3.1 Gen 2 = 10 Gbit/s
- USB 3.1 Gen 2 + display port alternate mode
- Thunderbolt 3 supports everything of the above but no display port alternate mode

Sounds like a fun experience.
 
No, it's even better, different options:
- Charging only (uncommon, but it's possible)
- USB 2.0
- USB 2.0 + display port alternate mode (uncommon, but it's possible)
- USB 3.1 Gen 1 = 5 Gbit/s, basically renamed USB 3.0
- USB 3.1 Gen 1 + display port alternate mode
- USB 3.1 Gen 2 = 10 Gbit/s
- USB 3.1 Gen 2 + display port alternate mode
- Thunderbolt 3 supports everything of the above but no display port alternate mode

Sounds like a fun experience.
All these with a USB-C form factor? What a mess! So you have to label them, if you have different versions?
 
All with the same USB-C form factor, right.
I wonder how many people will return their Thunderbolt 3 to Thunderbolt 2 dongles, because they wanted to use it for mini Display Port and nothing is showing on the display.
 
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That's the thing.
I totally get that a smartphone or some IO like keyboards etc. don't need all USB-C features, so they aren't implemented into their ports.

But why start screwing around with cables as well? Just to save a few cents?

I'm excluding Thunderbolt because it's expensive and needs chips inside the cable's plugs, but USB-C should be USB-C and not one of 7 versions of USB-C.
 
There are usb-c / thunderbold data cables labled with a lightning sign - these cables work well with the samsung ssd. I had the same problem using the thunderbolt 3 port on a Dell Precision 5510.

BTW. the Apple usb-c power cable is not "thunderbolt" labled, it is clearly stated that the usb-c power cable is only for powering usb-c devices / Macbook Pro's meant.
 
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