External USB C SSD

Discussion in 'Mac Accessories' started by BJB Productions, Mar 1, 2017.

  1. BJB Productions macrumors 65816

    BJB Productions

    Joined:
    Nov 10, 2008
    #1
    Are there any decent options out there for a USB C Thunderbolt external SSD? Such as for a working drive. I can't afford the new fancy LacIe drives.

    Thanks!
     
  2. afallnstar macrumors member

    afallnstar

    Joined:
    Sep 9, 2007
    Location:
    Seattle
    #2
    Check out the G Technology G-Drive Slim SSD USB-C. Quite a mouthful but a decent drive.
     
  3. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #3
    I just bought this USB-C enclosure and popped a Samsung EVO SSD in it. Works perfectly.
     
  4. anson42 macrumors regular

    Joined:
    Mar 13, 2014
    Location:
    Oakland, CA
    #4
    I recommend this approach as well. Grab a respected USB-3 enclosure and low cost SSD drive and put together your own accessory. You don't need a Thunderbolt enclosure, a USB-3 (using USB-C connector) will suffice. TB is overkill for the transfer rate of single SATA and PCIe SSDs unless you need the daisy chain capability of TB peripherals.
     
  5. BJB Productions thread starter macrumors 65816

    BJB Productions

    Joined:
    Nov 10, 2008
    #5
    Thanks! I ended up purchasing a Samsung 250gb m.2 as a working drive to put in my new enclosure. However, If I could ever find a usb-C case to put it in, I may make it portable. Would USB-C Bottleneck the speed of the m.2?
     
  6. anson42 macrumors regular

    Joined:
    Mar 13, 2014
    Location:
    Oakland, CA
    #6
    What enclosure did you put it in? If your enclosure has a USB-3 port (e.g. a USB-3 micro B or type B) then you have no worries about a bottleneck. There's no need to get a USB-C enclosure where the only difference would the connector if USB-3 is the protocol.
     
  7. ZapNZs, Mar 7, 2017
    Last edited: Mar 7, 2017

    ZapNZs macrumors 68020

    ZapNZs

    Joined:
    Jan 23, 2017
    #7

    As I am actively learning in this area, someone can clarify or correct me if I am wrong. To my understanding...

    Whether or not USB becomes your bottleneck will depend on the drive & the enclosure you purchased:

    If you purchased a m.2 SATA SSD like the Samsung 850 Evo m.2 and a USB 3.1 gen2 enclosure...
    These drives peak at around 550 MB/s as they are limited by SATA 3's saturation. USB 3.1 gen2 goes up to something like 1,200 MB/s IIRC as its theoretical peak - with a good USB 3.1 gen2 m.2 SATA enclosure, you should saturate the drive's capability (and hence get read/write speeds approaching the drive's limits.)

    If you purchased a m.2 SATA SSD like the Samsung 850 Evo m.2 and a USB 3.1 gen1 (USB 3.0) enclosure...
    If your enclosure is legacy USB 3.1 gen1 (formally known as USB 3.0, where you would use a C-->microA cable), then you will still get good speeds, but you will probably not quite max out the drive. 300-400 MB/s may be more of a realistic expectation, even though USB 3.1 gen1 has a theoretical peak of around 600 MB/s (with theoretical being the key word.)

    A potential bottleneck for both of the above is the chipset in the enclosure, as I've found that some of the less expensive m.2 enclosures yield read/write speeds well below what the SSD and interface support, and lower than what other m.2 enclosures with the same SSD/interface are capable of.

    If you purchased a m.2 PCIe SSD like the Samsung 960 Evo or 960 Pro...
    USB will be a huge bottleneck, regardless of the version - The Samsung 960 Pro can read up to something like 3,500 MB/s and write something like 2,500 MB/s. So you would need ThunderBolt3 to take full advantage of the 960 Pro (along with an expensive enclosure) or ThunderBolt 2 (which would still not quite max the SSD.)
     
  8. anson42 macrumors regular

    Joined:
    Mar 13, 2014
    Location:
    Oakland, CA
    #8
    I think you're spot on. USB3 gen 2 theoretically supports up to 10 Gbps (gigabits/s) and the new m.2 PCIe SSDs can do 2500MB/s (megabytes/s) == 20 Gbps so USB 3 gen 2 would be a bottleneck at maximum theoretical transfer speeds.
     

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