Picked up a new small external drive.
Samsung T3.
The read/write is pretty good, definitely for a tiny external I can have in my pocket or go bag.
I threw in some pics of the drive and compared to the size of a normal size SSD in the smallest external enclosure I have.
The T3 is a USB-C drive. The connection to the drive itself is USB-C, the cable that comes with the drive is USB-C on one end and USB-A on the opposite end.
Also mileage may very with cables.
I thought this drive would have come with a USB-C - USB-C cable. It didn't so I used the only strictly USB-C cable I have with me which is the one that came with my retina 12" MacBook.
This one only allowed transfer at around 34MB/s....no good.
The second was just another USB-C cable I had lying around. It also only transferred at roughly 34MB/s.
Ok by now I'm thinking the drive my be the issue.
Finally I found my USB-C to USB-A adapter
https://www.amazon.com/gp/product/B013FGW5US/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
and used the cable that came with the T3.
So USB-C into the T3, USB-A into the adapter then the USB-C end of the adapter into the new MacBook Pro.
Finally I got 300+MB/s from the drive.
So, I'm going to need to do some shopping around to find some true USB-C 3.0 actual speed capable cables.
It's crazy to me not all of them are even capable of the speeds advertised by USB-C.