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thevisi0nary

macrumors newbie
Original poster
Mar 20, 2021
13
2
Using MBA M1.

If max (theoretical) speed of my sata ssd is around 500-550 mbs, and the limit of Usb 3.0 is 500 mbs I'm not losing much in the very best case scenario getting a Usb 3.1 enclosure. Is there any other benefit to Usb 3.1? Like controller latency or something else?
 

Fishrrman

macrumors Penryn
Feb 20, 2009
29,248
13,323
The advantage of USB3.1 gen2 is speed (but you need an nvme SSD to achieve it).

A SATA SSD in a USB3 enclosure will yield read speeds around 420MBps.

If you put the SATA SSD in a 2.5" enclosure that supports USB3.1 gen2, you will probably get some more speed from it, perhaps close to 500MBps. The difference won't be overwhelming, but may still be noticeable...

An nvme blade SSD in a USB3.1 gen2 enclosure will yield read speeds around 800-850MBps.
 

thevisi0nary

macrumors newbie
Original poster
Mar 20, 2021
13
2
The advantage of USB3.1 gen2 is speed (but you need an nvme SSD to achieve it).

A SATA SSD in a USB3 enclosure will yield read speeds around 420MBps.

If you put the SATA SSD in a 2.5" enclosure that supports USB3.1 gen2, you will probably get some more speed from it, perhaps close to 500MBps. The difference won't be overwhelming, but may still be noticeable...

An nvme blade SSD in a USB3.1 gen2 enclosure will yield read speeds around 800-850MBps.

Correct, in this case it's only for a sata ssd. Max speed of the sata drive is between 500-550mpbs and max bandwidth of Usb 3.0 is 500mpbs, so I'm not worried about the top theoretical speed in this case as the absolute fastest my sata drive can go is marginally faster than Usb 3.0 anyway. I'm just wondering if there are any other things worth considering as far as Usb 3.1 like better controller latency or bus power delivery.
 

mj_

macrumors 68000
May 18, 2017
1,618
1,281
Austin, TX
USB is a hot mess, and the USB consortium really f-ed things up big time in order to create mass havic and confusion.

USB 3.0 = 5 Gbit/s

USB 3.1 Gen 1 = USB 3.0 = 5 Gbit/s
USB 3.1 Gen 2 = 10 Gbit/s

USB 3.2 Gen 1x1 = USB 3.2 Gen 1 = USB 3.1 Gen 1 = USB 3.0 = 5 Gbit/s
USB 3.2 Gen 1x2 = 10 Gbit/s
USB 3.2 Gen 2x1 = USB 3.2 Gen 2 = USB 3.1 Gen 2 = 10 Gbit/s
USB 3.2 Gen 2x2 = 20 Gbit/s

And don't even get me started on USB 4...

A standard SATA III interface offers a maximum speed of 6 Gbit/s. In other words: yes, a USB 3.1 enclosure might be slightly faster than a USB 3.0 enclosure if it happens to be of the Gen 2 10 Gbit/s variety but chances are you won't notice the difference.
 
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