Optimize speed of USB3.1 gen2 external NVMe box

While migrating from an 1TB to a 2TB NVMe I needed to copy approx. 0.7TB of files to the new NVMe. I have put it into a Sabrent EC-NVME external, USB3.1 gen2 enclosure intended for NVMe drives:

 

I have connected the USB-C connector of the enclosure to a USB3.2 gen2 USB-C connector of my ThinkPad X1 Extreme Gen3 laptop running Windows 11 (most probably applicable to Windows 10 as well).

Also copying from a built in NVMe, the speed was supposed to max out the USB3.1 gen2 connection that is 10Gbps, so should copy at up to 1000MB/s as per product specs. 

My copy speed however was only 38-42MB/s. Later I realized this was actually maxing out the limitation of USB2 (!!!).

The things that did not help (a lot):

1. Finding the Disk in Device manager and changing the policy to better performance:
   
   
2. Disabling indexing for the drive:
   
   
3. Updating the firmware of the Sabrent device using the utility downloaded for their support site.
4. Replacing the USB-C to USB-C cable with a brand new one. 
5. Checking that the port I connected is at least USB3.1 gen2, indeed it is USB3.2 gen2 & ThunderBolt 3.
   

 Finally I have got a hint to check the messages of the devices connected under Control Panel > Hardware and Sound > Devices and Printers (on Windows 11 that takes you to "Settings > Bluetooth and devices > Devices" if you click "View more devices"):

 

After figuring out that the JM583 was che chip used by the Sabrent device what gave it away was the message at that time underneath the JM583 device: ""Device can perform faster when connected to USB 3.0". 

Thus I figured that there is a connection problem. Then I remembered that provides a USB-C to USB-A cable with and extra cap to enable plugging into USB-C on the computer end too (see photo above).

I dug that cable up and voila: the message in "Bluetooth & devices > Devices" changed into "Connected to USB 3.0" and the copy speed went up to around 410MB/sec!

 This is still not perfect as it seems to be the 5GB/sec limitation of USB 3.0 a.k.a. USB 3.1 gen1, but still ten times better than the USB2 speed. 😊

The moral of the Story: it seems that neither USB3.2gen2 not ThunderBolt3 are compatible with the only slightly slower USB3.1gen2 speeds, and using USB-C might make the connection revert to a USB2.0 compatibility mode...