Extremely slow external SSD speeds MacBook Pro 2016

Discussion in 'MacBook Pro' started by sguser, Nov 17, 2016.

  1. sguser macrumors regular

    Aug 12, 2010
    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?
  2. maflynn Moderator


    Staff Member

    May 3, 2009
    Did you try another USB port see if its perhaps a specific port.
  3. sn00p macrumors regular

    Nov 10, 2009
  4. sguser thread starter macrumors regular

    Aug 12, 2010
  5. blackhawk10 macrumors member

    Feb 28, 2014
    Did you use the left side USB-C ports? Only the left-side ports offer full-bandwidth Thunderbolt 3 performance
  6. c.s. macrumors regular


    Nov 11, 2007
  7. sguser thread starter macrumors regular

    Aug 12, 2010
  8. cmaier macrumors G4

    Jul 25, 2007
    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.
  9. arbitrage macrumors 6502a

    Mar 19, 2009
    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.
  10. sguser thread starter macrumors regular

    Aug 12, 2010
    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...

  11. bent christian Suspended

    bent christian

    Nov 5, 2015
    Totally glad I bought last year. Apple is a complete mess in 2016.
  12. Wowereit macrumors 6502a

    Feb 1, 2016
    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.
  13. vddobrev macrumors 6502

    Oct 28, 2016
    Haskovo, Bulgaria
    All these with a USB-C form factor? What a mess! So you have to label them, if you have different versions?
  14. Wowereit macrumors 6502a

    Feb 1, 2016
    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.
  15. Bryan Bowler macrumors 68040

    Sep 27, 2008
    I thought USB-C was the one cable that was going to replace them all? :confused:
  16. Wowereit macrumors 6502a

    Feb 1, 2016
    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.
  17. radus macrumors 6502

    Jan 12, 2009
    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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