kanex thunderbolt to usb 3 + ethernet adapter.

[jobesucks]

Anyone here using a kanex thunderbolt to usb 3 + ethernet adapter.
I have a mid 2011 iMac with only usb 2 so got the above adapter to add usb3. I've attached a Sammy 850 evo 250Gb to it via a sabrent usb3 to sata adapter (same drive as I've added internally). Running Aja system test and black magic I'm only getting 355MB/s read and write, from external yet get approx 500MB/s from the internal drive. Should there be this much difference between the 2 interfaces, using identical drives?

 

[casperes1996]

Theoretical maximum for USB 3.0 is around 600mbps. Now there's a lot of overhead and whatnot to consider, but you do seem to fall well below that. Then on the other hand (see attached image) this is a test done by MacWorld, and there can be quite a difference between using Thunderbolt/PCIe and USB.
Does the USB-SATA adapter you use support UASP? macOS does not right now as far as I've been able to gather, but the connectors that support it are also usually just a lot faster than those who don't.
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[jobesucks]

Thanks for reply. Yes adapter does support uasp. Supposed to be optimised for SSD. Thing is it is constant 355MB/s read and write with no fluctuations, as though it's topped out at the adapter(either the sata or the kanex) or it could just be I'm going through 2 adapters.

 

[casperes1996]

Thanks for reply. Yes adapter does support uasp. Supposed to be optimised for SSD. Thing is it is constant 355MB/s read and write with no fluctuations, as though it's topped out at the adapter(either the sata or the kanex) or it could just be I'm going through 2 adapters.

Definitely sounds like there's a bottleneck somewhere, though I don't know where it is.

 

[Fishrrman]

OP wrote:
"I'm only getting 355MB/s read and write"

On a Mac with native USB3, the "max" for an SSD connected via USB3 (with an adapter that supports UASP) is about 432mbps. I have never seen a report of one running faster.

Considering that you're factoring into the mix ANOTHER "converter" of sorts (the Kanex adapter), I'd say you're getting about all you're going to get...

 

[jobesucks]

OP wrote:
"I'm only getting 355MB/s read and write"

On a Mac with native USB3, the "max" for an SSD connected via USB3 (with an adapter that supports UASP) is about 432mbps. I have never seen a report of one running faster.

Considering that you're factoring into the mix ANOTHER "converter" of sorts (the Kanex adapter), I'd say you're getting about all you're going to get...

Yep figure so, not complaining thats plenty fast enough, just curious as to why such a big difference with the same drive internal.