I've been testing a USB 3.1 Gen2 external enclosure quite extensively (it's had some issues, went back to supplier, they couldn't find issues, so sent it back with a known-good cable and I'm testing some more). As part of this, I had it plugged into the supposedly USB3.0 (5Gbit) type-A ports on the Mac mini. Except, under System Information, it showed up as being 10Gbit still, and it performed at exactly the same speeds as when plugged into the type-C ports. When I had it plugged into a known 3.0 port (on an Akitio TB dock) it showed as 5Gbps and the read/write speed was reduced somewhat. Apple say the type-A ports are only 5Gbps - has anyone else had a 10Gbit device plugged into the A ports and had it show up/perform as 10Gbit??