Distinguishing between usb2 vs. usb3 cables?

Discussion in 'iMac' started by kat.hayes, May 17, 2019.

  1. kat.hayes macrumors 65816

    Oct 10, 2011
    I have a bunch of old USB cables. I need to plug in an external drive. Is there some way to distinguish USB2 vs. USB3 cables?

  2. Ulenspiegel macrumors 68040


    Nov 8, 2014
    Land of Flanders and Elsewhere
    USB 3.0 Connectors are different from USB 2.0 Connectors and the 3.0 connectors are usually colored blue on the inside in order to distinguish them from the 2.0 connectors.
  3. mikehalloran macrumors 65816

    Oct 14, 2018
    The Sillie Con Valley
    That’s the Type A connector on one end. The other end will be stacked or flat with a crease.

    If you have to ask, it’s a USB 2 cable.
  4. dwig macrumors 6502a

    Jan 4, 2015
    Key West FL
    Check out this link:

    It is possible, but difficult, to distinguish the difference in the USB-A connectors. The additional data lines use contacts deep inside. Many USB3 cables will use a blue insulator on the USB-A plugs which helps. If the other end uses a standard USB-B or one of the mini or micro connectors it is easy to tell. The USB3 B and micro-B connectors are easy to recognize and any mini-B variant indicates it is a USB2 cable. On rare occasions, one of the various USB logos will be molded into the plugs to indicate the USB class.

    If the cable is USB-A to USB-C you can only use for USB-A connector for any chance of telling visually. If it is a USB-C to USB-C cable there is no way to tell visually unless one of the USB and/or TB3 logos are molded into the plugs (a rare occurance). It could be USB2, USB3.1gen1, USB3.1gen2, or even TB3.
  5. kat.hayes thread starter macrumors 65816

    Oct 10, 2011
    I recently moved so I had all of my new cables and old ones mixed into a box. Is there someway within Mac OS to check the transfer speeds?
  6. Fishrrman macrumors P6


    Feb 20, 2009
    "Is there someway within Mac OS to check the transfer speeds?"

    The only way I can think of is to "try each one and see what you get".

    Pick a "known good USB3 drive".
    Then connect it to the Mac with each cable.
    Once connected, run something like BlackMagic Speed Test on the drive and record the results.
    Then, disconnect and re-connect with the NEXT cable. Repeat.
    Etc. Etc.

    As mentioned above, the USBa cables with the "blue ends" are USB3.
    I would assume that if it DOES NOT have the blue end, it's either USB2 or even USB1.
  7. dwig macrumors 6502a

    Jan 4, 2015
    Key West FL
    Fishrrman's Trial-and-Terror approach is the only way to test.

    I have some USB3 cables from early on that do not have the "blue end" (insulator inside the USB-A plug) and my 6 year old desktop, which has a mix of USB2 and USB3, doesn't use the blue color-coding on the USB3 connectors either. If the end is blue there's a 99.9% chance it is USB3 (there are likely some cheap bogus cables out there that lie) and if it is not it could be anything.

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6 May 17, 2019