The Mac Mini M1 Sub-Par Speed Of USB-C Devices Connected To Thunderbolt 3

 Something is up with the Mac Mini M1 when connecting USB-C devices rated 10Gbps. They don't show up as such, instead they are downgraded to 5Gbps.

I noticed that the Phantom Drives DUO was only recognized as a 5Gbps device on my Mac mini System Report, even though it is advertised as a 10Gbps device on Phantom website. And I picked this enclosure because of the advertised speed.

Only I am not getting the speed I should get, instead it maxes out at around 360MB/s, that matches the theoretical 5Gbps max speed.

Same thing with the OWC Mercury Dual Mini enclosure, advertised at 10Gbps, actual tested speed around 360MB/s.

And on top of this, the same dual SSD Raid 0 array reaches 690-800MB/s on a Sonnet Pcie card, which is the expected speed for such an array.

I'm not the only one seeing this, as mentioned in this Reddit post:

What the heck Apple? So if the 10Gbps devices are only operating at 5Gbps with TB3, and the other USB ports are also 5Gbps, what are we supposed to buy to get the 10Gbps speed we want?

Are we forced to upgrade to 40Gbps TB3? Not many devices on the market, all much more expensive than USB 3.1 10Gbps. I understand why now.

And what about USB4? Do these devices even exist? Looks like compatibility is not even guaranteed ?...

UPDATE 1:

Oh boy, there is more to this problem in this Apple Discussion thread. Someone mentions a "bug" in macOS, someone else mentions "Some of those folks have found that using a Thunderbolt3 cable instead of a USB-C cable returned stability and performance."

Damn! I don't have a Thunderbolt3 cable at the ready to test this. That would be dandy if true.

UPDATE 2:

I ordered a Thunderbolt3 cable and I am sad to say that this solution DOES NOT WORK for me with the Phantom Drives DUO external enclosure. I have the same exact speed with USB-C cable or with Thunderbolt3 or Thunderbolt4 cables. Not good.

Speed with Thunderbolt3 cable, same as with USB-C cable

Speed with Thunderbolt4 cable, same as with USB-C cable

Sub-par speed with USB-C cable. Should be in the 800MB/s.

So at this point I will be returning the Phantom Drives enclosure. I already parted with the OWC Mercury Elite Pro Dual Mini, so I can't test it with a Thunderbolt cable unfortunately, but I don't really fancy the form factor anyway. If someone would be kind enough to do the test and add comments below that'd be great.

What's left? I guess there is no solution for using the Sonnet TSATS6 in a Thunderbolt3 PCIe enclosure. Being 12.28" in length it does not fit in the Highpoint RocketStor 6661A (max 7.87") or most Sonnet PCIe Enclosure that are half-length as well.

It would fit in the $899 Sonnet Echo3.  But whoa! That's an expensive box! And it certainly reduces the portability. I could fit two other cards in the enclosure in addition to the Sonnet dual SSD. My BMD Mini Monitor would go in right away. And later I could upgrade to a Mini Monitor 4K or a Decklink. And I would still have a third slot available... For what though?

I think for the time being I will use the SSDs as two separate 1TB drives and just forget Raid 0. Instead I will maybe start looking again for a 4 or 8 drives bay fit with HHDs.