MetropleX Intel(R) USB 3.10 eXtensible Host Controller - 1.20 (Microsoft). Have tried with a USB hub connected with a SSD plugged in. I've also tried with the sole phone connected to the USB c port. The latter option does give me 3 hour estimate as opposed to 10+ hours. Also, when accessing a large folder, 10 gig plus full of media, it takes several minutes for Windows Explorer to load the files (not just the thumbnail preview) in the window.