I recently acquired a Inateck USB 3.0 to SATA Dual-Bay Docking Station with UASP support. I was curious what it's performance was, and then got curious about comparing it to the internal drive.

My machine is an XPS 8930, I7-8700,  with 32 GB memory, 1 x 2TB internal HDD and 16GB of Optane Memory. I connected the Inateck to the USB 3.0 Gen2 port on the back of the machine. I had a Dell 500 MB 5.25 HDD in one of the slots with a variety of video files (large files). I also created 2 Ramdisks of 6GB each so as to emphasize transfer speeds over the USB connection. I ended up running the following tests with the results stated. Note up front - these results were the end to end results of moving 5.14 GB of data contained in 13 files.

USB -> Ramdisk  : ~128 MB/s  - Fairly level result throughout test

USB -> HDD         : ~ 128 MB/s - Nearly identical

Ramdisk -> HDD   : ~110 MB/s -  Very high initial rate then big slow down

Ramdisk -> Ramdisk: ~2.1 GB/s  - No real surprise here

HDD -> Ramdisk     :  165 MB/s  HDD's should have better read speed than write speed

HDD -> HDD        : ~60 MB/s - but much greater variances in speed throughout with much higher initial rate

I guess what surprised me the most was that the net transfer speeds from the USB were not really much different than the HDD speeds.  Makes me wonder what an external enclosure with SSD & UASP would do. I'm guessing not much different as I'm guessing that effectively the USB 3.0 gen2 connection is maxing out at about 1 Gbs.