[JohnR]

I decided that one of the things I would do during my recent vacation is update my computing system. That way, I could hit the ground running when I start work again.

One thing I figured would make sense is a very fast external drive enclosure. "Fast" as in Thunderbolt speeds. It turns out that, unless I am missing something important, if you look at Apple's laptops made in the last three years, it is not possible to buy a single fast drive that works with all of them.

• 2015 Macbook Pro - Thunderbolt 2
• 2017 Macbook Pro - Thunderbolt 3
• 2017 Macbook - USB-C

Now, I don't have either of the latter 2, but I might in future so don't want to spend $ on a fast drive now that won't work natively with the next laptop.

But I can't find one...! There is no external fast drive that will work with all of those three laptops.... (Is there?) It looks like USB3 is still the only option if you need a drive that works with all recent Apple laptops. (I assume that USB-C will work with USB3 on the drive end if you have the right cable, but I'm not even sure about that...)

Cor blimey   

[Jonathon Janusz]

USB3 with a USB Type C connector will be your lowest common denominator that will work (with adapters) across all three, but depending on which revision of USB3 your drive runs, you will be limited to a max of either 5 (USB3.1 on the Macbook or the 2015 MBP) or 10Gps (TB2 on the 2015 MBP, which can actually push 20Gps if running as a TB port to a TB2 or TB3 device, but maxes out at 10Gps when connecting to a USB3.1rev2 - the max speed of the USB3.1rev2 spec - device) throughput. (Neither the Macbook or the 2015 MBP have USB3.1rev2 to get 10Gps out of their USB ports; the 2017 MBP can do that USB speed on the TB3 ports, but it is kind of a moot point with a native TB3 drive capable of connecting and running faster than that).  Getting a thunderbolt 3 drive with a USB Type C connector will get you the fastest speeds with the two thunderbolt compatible macbook pros (with an adapter for the older TB2 MBP), but leaves the USB-C only Macbook out in the cold (a TB drive will not work on the USB only port).

To make sense of USB3 vs. USB-C, think of USB-C (or correctly USB Type C) as only a type of connector; USB3, TB3, HDMI, DP, etc. are all just "protocols" that can run on a cable designed for each of them that would happen to have a USB Type C connector on the ends.  The confusing part for consumers is that now there is one kind of "end" on the cable, but a variety of different kinds of cables (and some of them are not compatible with each other, to the point of damaging the stuff plugged together if you use just the wrong one at the wrong time) that all can have the same kind of ends on them...

If it were me and I were you (and based on your owning a MBP now and likely another MBP rather than a MB in the future, and that at some point Apple is going to have to bend and put a TB3 port on some future revision of the MB), I would go with a TB3 drive with a USB Type C connector, get an adapter to convert down to your TB2 port now, and be set for what is the current generation newest/fastest thing that will only go faster for you when you upgrade to your next laptop.

[JohnR]

Thanks Jonathon. I didn't know I could connect a TB2 port to a USB3.1 drive, but it seems that an adapter is needed there too. Comments on the Apple site/store on the adapter suggest that it doesn't work very well if at all in that direction i.e. maybe it is designed to work the "other way".

I will look into the TB3 drives.

Curiously I just went to youtube for something and it shows this to me: https://www.youtube.com/watch?v=MKJjLwMUPJI (rant about connectors at about 1:40)