The iPad Pro's (only 10.5 and 12.9) have 16 pins in the port for that capability and Apple even discloses that USB 3 speeds only are achieved on those specific models, the 9.7 is excluded because it and all other lightning devices still only have 8 pins. Also the iPad Pro's, 10.5 and 12.9 only, were specifically called out to have USB-C controllers that allowed them USB 3.0 function and those have not appeared yet in any iPhone. There are postings around that have confirmed that when connected with the Lightning to USB-C cable, the iPhone's still only report back USB 2.0 speeds.Source? iPad Pro became USB 3 with the introduction of 512GB. I would imagine the XS/Max are the same. That was over a year ago.