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What does USB 3.1 mean in System Information? Why am I not getting full speed on my SSD?

I have an M1 4 port 2021 Mac.

Trying to find out if there really is any difference between the Thunderbolt ports and the USB ports.

I have an OWC Envoy Pro USB-C drive and it's only a little faster on the Thunderbolt/USB-4 ports. The OWC site claims that AJA gives readings of 1002 MB/sec for write and 992 MB/sec for Read. I only get about 700 MB/sec. Latest reading (using AJA, as OWC does) is W: 787 R: 675 on the Thunderbolt/USB4 port.

And in the System Information report, what does USB 3.1 mean?

5 Gbit/s - USB 3.0 USB 3.1Gen 1 - ESB 3.2 Gen 1 - SuperSpeed USB

10 Gbit/s - USB 3.1 Gen 2 - USB 2.3 Gen 2 - SuperSpeed USB 10 Gpbs

It is almost beyond belief that the USB consortium (or standard board, or whatever) came up with their awful, confusing naming scheme. Just tell us if it's 5, 10, or 20. Sheesh.

Oh, I'm using an OWC Thunderbolt 4 cable. It's supposed to do all protocols, speeds, whatever, IIRC.

Oh^2: I'm using the Thunderbolt port on the Mac, and nothing comes up under Thunderbolt/USB4. The SSD comes up under USB under USB 3.1 Bus.

TIA!

iMac (M1, 2021)

Posted on Jul 23, 2023 11:31 AM

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etresoft

Level 9

56,314 points

Posted on Jul 23, 2023 3:39 PM

betaneptune wrote:

The fine print says iMac Pro. So it's not apples to apples. I guess that's reasonable that I'm getting less speed: 7xx vs. 1002/992. Is that right?

The fine print is key on that page. For one thing, it says "Thunderbolt compatible". That should be a red light right there. It actually uses the word "Thunderbolt" 3 times on that page. But it's not Thunderbolt at all.

There are two screenshots on that page. The one for Blackmagic is much closer to your speeds. Any published result from those speed test apps should be considered suspect. For one thing, they always talk about video stuff and use absurdly large file sizes. 64 GB in this case. How many 64 GB files do you need to copy? Or have? Plus, it was a single file test. Any performance test on a non-embedded system like this should be considered invalid. You have to run several tests and take the average. But when advertising, they are more likely to run several tests and publish the best. Slight difference there. 😄

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betaneptune Author

Level 2

220 points

Jul 24, 2023 5:14 PM in response to Servant of Cats

What a mess! Ugh.

Here's the secret code chart I have for USB: So the only thing that really matters for USB 3 is the Gen or just the speed. The x in 3.x appears to have no meaning whatsoever. Do I have that right? USB4 and Thunderbolt seem to require a book-length manual. 3/4 ALT mode?

Hmmm. Maybe it is just Apple world. I have yet to see anything that is or supports USB 3.2 Gen 2x2 up to 20 Gbps.

Here's my secret code chart. Unfortunately, it doesn't include USB 4.

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betaneptune Author

Level 2

220 points

Jul 25, 2023 10:53 AM in response to HWTech

The information you provided is very useful. Thank you very much! But it doesn't answer the first question.

Which 3.1 is meant in the System Information USB panel? Gen 1, Gen 2 or either? Seems to me it should be more specific. I assume it's at least the 10 Gbps version, but maybe it means it could be Gen 1 or Gen 2.

BTW, I tested with a file of video footage, not an FCP library, e.g., which has a huge number of folders (as can be seen by clicking "Show Package Contents"), which "create" a large amount of overhead. I got at least that much right!!!

Jul 23, 2023 11:39 AM in response to betaneptune

“… It is almost beyond belief that the USB consortium … came up with their awful, confusing naming scheme … “

LOL.

They’ve worked for over 20 years to get the current level pf confusion. .

betaneptune Author

Level 2

220 points

Jul 23, 2023 11:51 AM in response to Chattanoogan

"They’ve worked for over 20 years to get the current level pf confusion. . "

LOL, too! (^_^)

etresoft

Level 9

56,314 points

Jul 23, 2023 12:06 PM in response to betaneptune

betaneptune wrote:

So in Sys Info, USB means 10 Gbits/sec?

At best, it means "up to 10 Gbits/sec".

If the product is already discontinued, no one can even look at it themselves.

betaneptune Author

Level 2

220 points

Jul 23, 2023 6:03 PM in response to Servant of Cats

Didn't know! Thanks for the info.

betaneptune Author

Level 2

220 points

Jul 23, 2023 6:04 PM in response to etresoft

Oops! I meant USB 3.1, of course.

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What does USB 3.1 mean in System Information? Why am I not getting full speed on my SSD?