I recently bought my new macbook pro 2017 model which comes with USB Type-C ports supporting thunderbolt 3 standard with USB 3.1 standard. So since I have lots of devices with USB A type and supporting USB 3.1 standard, thought to buy some adapters. But when I'm shopping to buy them I saw that most companies have claimed that their USB Type C adapters are supporting USB 3.0 standards instead of 3.1 and couldn't find any adapter (which satisfies my needs) supports USB 3.1 standard. I was kinda confused now and have to problems to solve before buy them.

1) Since my devices supprt USB 3.1 and Macbook supports USB 3.1 standard, will those adapters (which claim to work fine with UBS 3.0 ) deliver the speed of USB 3.1?

2) Those companies have claimed that those adapters are working with USB 3.0 standard because USB 3.1 is quite young?

  • \$\begingroup\$ USB 3.1 is backwards compatible with USB 3.0 so (disregarding driver and software issues) a USB 3.0 device will just work with the Macbook. For a plug adapter/connector there is no electrical difference between USB 3.0 and USB 3.1, the connections are the same. If you're lucky an adapter rated for USB 3.0 will support the USB 3.1 speed. If not then you'll get USB 3.0 speed which is still pretty fast. There are very few peripherals where you could even notice the difference between USB 3.0 speed and USB 3.1 speed. Yes USB 3.1 is new and not common yet so you cannot expect guarantees yet. \$\endgroup\$ – Bimpelrekkie Sep 4 '17 at 13:42
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    \$\begingroup\$ "Since my devices supprt USB 3.1 and Macbook supports USB 3.1 standard, will those adapters [...] deliver the speed of USB 3.1?" Probably not, probably none of your devices deliver data at USB 3.1 nor USB 3.0, all them are at USB 2.0 60 MB/s or less. \$\endgroup\$ – pasaba por aqui Sep 4 '17 at 14:27

Here needs to be a small clarification. The compliance to USB 3.1 standard can mean anything, even a mouse can be declared "USB 3.1", because 3.1 includes all modes for USB 3.0, which means USB 2.0 at high-speed, full-speed and low-speed modes. However, when seeing "USB 3.1", most people would assume that the interface will give them speeds at 10 Gbps rate, so-called Gen2 speed.

Unfortunately, up do date (Sept. 2017) there are very few peripheral devices that work at Gen.2 speeds. While there are some pilot reviews of Gen.2 flash drives, very few are practically available to public, practically none. The only device known to me is the USB-SATA bridge (found in USB enclosures) based on ASMedia ASM1351 Gen.2 chip.

Therefore, even if the Macbook does have the USB 3.1 Gen.2 capability, there is not much you can get out of this.

To use your legacy "3.1" peripherals with Type-C port you can use either "legacy cable assemblies" (Type-C to micro-B cables), or use an adapter. Adapting Type-C to legacy Type-A requires only passive wire connections. I would strongly suggest to use "mini-adapters", since they are based on a single small PCB between Type-C and Type-A, and don't involve hand-soldered cables. These mini-adapters should have much better chance to support Gen.2 speeds, if you have it. Still some experimentation will be required to see if these adapters work at Gen.2 speeds, people do very weird things in these simple devices.


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