Trim support over USB C 3.1

Discussion in 'iMac' started by PJivan, Jul 7, 2017.

  1. PJivan macrumors 6502

    PJivan

    Joined:
    Aug 19, 2015
    #1
    So trim support was not supported by USB controller 3 of the old iMac and only via thunderbolt 2.
    Now there are 2 ports thunderbolt 3/USB C 3.1, question is, does the TRIM support works for USB-C?
     
  2. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #2
    Not on USB
    If you think that enabling trim is important, then use a Thunderbolt connection.
     
  3. satinsilverem2 macrumors 6502a

    satinsilverem2

    Joined:
    Nov 12, 2013
    Location:
    Richmond, VA
    #3
    TRIM is supported over USB but the controller for the drive has to support UASP.
     
  4. EugW macrumors 601

    EugW

    Joined:
    Jun 18, 2017
    #4
    I'm not sure that is enough, but where do you see UASP support listed? For my Samsung 850 EVO with USB 3 UASP-compatible SATA dock, I still get some serious slowdowns with heavy use. As in down to less than 1 MB/s speeds in extreme cases. If I let it sit for while, the speeds return. I'm guessing that TRIM is not working here (and I don't see TRIM support listed), and it's just taking its time with garbage collection. Does that make any sense?

    I don't see UASP mentioned in the system report though. Does that mean I'm just not getting UASP support? I am thinking it must though, since I'm getting speeds of 430 MB/s on a clean drive over USB 3, which I didn't think was possible without UASP.
     
  5. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #5
    No, UASP provides support for the much-higher speed that an SSD offers - but does not provide trim support. It's still a limitation of the storage support on USB.
    You do have to decide if trim is really that relevant now (and is a hurdle that everyone must leap over)
    Not everyone agrees.
     
  6. EugW macrumors 601

    EugW

    Joined:
    Jun 18, 2017
    #6
    OK that makes sense. My dock is UASP enabled, and I do get higher speeds, but I see no evidence of TRIM support.

    And I think it matters, because with heavy usage on a somewhat full drive, speeds can slow to a crawl. Thus, if I were ever to go to external storage on my iMac, it would most definitely be Thunderbolt. Unfortunately though, I don't have that option with my MacBook. Too bad the MacBook does not support Thunderbolt. When does Intel add it for Y series machines? 2019?
     
  7. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #7
    Not exactly. Here is an older post of mine that explains a bit.

     

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