hit me like a bolt of lightning?!....most M1 Mac Thunderbolt ports don’t support USB 3.1 Gen 2....

[NewtonMP2100]

.....via testing....


Most M1 Mac Thunderbolt 4 ports don’t support the 10Gb/s transfers of USB 3.1 Gen 2, show tests

....Pro users of M1 Macs have reported disappointing transfer speeds with external SSDs, and tests appear to show that most M1 Mac Thunderbolt ports don’t support USB 3.1 Gen 2 – which means they don’t offer the maximum 10Gb/s transfer speeds that would be expected from Thunderbolt 4.

The tests were conducted on a 2021 16-inch MacBook Pro M1 Max, and a 2022 Mac Studio M1 Max

Background
We’ve discussed many times the mess and confusion caused by different USB-C standards, devices, and cables.

There is also a significant difference between theoretical and actual maximum speeds.

But tests suggest that most M1 Macs don’t support the USB 3.1 Gen 2 standard, making Thunderbolt transfers slower than they should be, in both theory and practice.

Eclectic Light summarizes the bottom line of the current speeds offered by different standards.

USB 3.0 onwards supports SuperSpeed USB at 5 Gb/s.
USB 3.1 Gen 2 adds SuperSpeed+ at 10 Gb/s.
USB 3.2 adds two-lane SuperSpeed+ at 10 and 20 Gb/s.

M1 Mac Thunderbolt 4 ports tested
Eclectic Light’s Howard Oakley carried out a series of tests with two M1 Macs:

Apple Mac Studio with M1 Max, 32 GB memory, 2 TB internal SSD, connected to an Apple Studio Display;
Apple MacBook Pro 16-inch, 2021 with M1 Pro, 32 GB memory, 2 TB internal SSD, using its internal display.

There are two ways of establishing the speed capabilities of a data connection. The first is to see what theoretical speeds are reported by the machine. Oakley first tested this with Intel Macs, to verify that his test SSDs and cables were definitely compatible.

Each was connected to an Intel Mac (including an iMac Pro) and it was verified that they established connection at SuperSpeed+ 10 Gb/s with those Macs.

Cables used included a certified Thunderbolt 4 model, and the USB-C (data) cables provided with the cases. Again, each was verified by establishing SuperSpeed+ 10 Gb/s connections to an Intel Mac.

Connection speeds were read from the SSD’s entry in the USB data given in System Information.

Second, measuring real-life speeds.

Transfer rates were measured using my free app Stibium, version 1.0 (55), which wrote a total of 160 files of sizes from 2 MB to 2 GB in size to a folder on the SSD being tested, and read those same files back (Series Write and Series Read Tests as detailed in Stibium’s Help reference). The procedure detailed as the ‘Gold Standard’ test was followed.

Oakley again compared Intel and M1 Macs, finding that real-life speeds were lower with the newer machines.

M1 Mac conclusions
The piece details the actual speeds achieved, suggesting the following conclusions. Key among them is that the fastest storage devices perform at about half their expected speeds; the limitation appears to be present in all M1 Macs; using a Thunderbolt 4 cable to connect a USB-C device to the front USB-C ports on a Mac Studio Max results in speeds below 10% of that expected; even the latest Mac Studio models don’t support USB 3.1 Gen 2.

Currently, and as far as I’m aware since their release in November 2020, no Thunderbolt port in any M1 model appears to fully support 10 Gb/s SuperSpeed+ in USB 3.1 Gen 2, at least for SSDs.
The only ports in M1 Macs which currently appear to support USB 3.1 Gen 2 fully are those on the front of the Mac Studio Max.
10 Gb/s SuperSpeed+ in USB 3.2 devices does appear to be supported by the Thunderbolt ports of M1 Macs.
For SATA/USB-C storage the impact on performance is limited, reducing transfer speeds from an expected 500 MB/s to 400 MB/s. For external storage used to store Time Machine backups, this isn’t likely to have any significant effect, as backup I/O is throttled anyway.
Greatest impact is likely with external storage capable of transfer speeds approaching 10 Gb/s, such as RAID arrays and NVMe SSDs with USB 3.1 Gen 2 rather than Thunderbolt 3. In those, expected transfer rates of 900 MB/s are likely to be reduced to less that 500 MB/s, doubling the time required to read or write files.
Users with USB 3.1 Gen 2 devices should connect them to a Thunderbolt 3 Dock, or the USB ports on a Studio Display, where they should perform better.
This shortcoming appears to have been present in all M1 Macs for nearly 18 months. If it’s a bug in the firmware of the Fabric core(s) responsible, it should have been fixed over a year ago. If it’s a fault in M1 series chips, then Apple should have informed users and qualified its claim for the compatibility of these ports.
Apple needs to investigate why using a Thunderbolt 4 cable to connect a USB-C device to the front USB-C ports on a Mac Studio Max results in unusably poor performance, below 10% of the transfer rates expected.
Lack of support for 10 Gb/s SuperSpeed+ in USB 3.1 Gen 2 is arguably the most serious failing in what has otherwise been a very successful transition.


not as Apple.....said......?!

[datbeme]

This is surprising. I know some of you here have NVMe SSDs in external enclosures, and I assume most would be USB C. For those that have an M1, what kind of transfer speeds are you getting?

[Tiangou]

10 Gb/s SuperSpeed+ in USB 3.2 devices does appear to be supported by the Thunderbolt ports of M1 Macs.

So, when possible you should buy certified USB 3.2 or Thunderbolt storage devices for your M1 Macs.

Good to know!

[MrNoBody]

my 2¢, putting a NVMe SSD in a USB 3.2 enclosure is like putting
cheap tires on a Ferrari F8 Spider.

[anonymouse1]

Well, the Thunderbolt ports on my M1 Mini work fine, as I recall-I'll double check after work.

I'd be leery of the USB4 Thunderbolt cable. I wonder what would happen if he used just a plain USB 3.2 cable....

[jonny]

My eternal drive will not stay mounted in the Mini's USB - C port.
I have to use it with a 3.2 type a cable.

[RAMd®d]

So, when possible you should buy certified USB 3.2


So these aren't cheap tires?

When I plugged my SanDisk Extreme Pro portable SSDs, they got maybe ~600Mpbs in my M1, and 900-1000Mbps in my 2018 mini.

A little research revealed the unsupported standard.

my 2¢, putting a NVMe SSD in a USB 3.2 enclosure is like putting
cheap tires on a Ferrari F8 Spider.


Maybe.

But my 2¢ is that I won't pass up a deal on an m.2 NVMe stick just because I've yet to find a reliable, moderately price TB4 box.

So I can continue to buy SATA SSDs and box that have no futureproofing, or I can take steps that put me in that direction.

Now, if I do find a good box and the price of good 1T or bigger m.2 sticks drops significantly below what I paid for my 8200 and 8100, I'll feel bad.

For a minute, then I move on.


This is surprising. I know some of you here have NVMe SSDs in external enclosures, and I assume most would be USB C. For those that have an M1, what kind of transfer speeds are you getting?


It surprised me when I tried my XPG 8200 with my M1 MBA, a few months back, and I'm surprised it din't raise more flags.

I was getting maybe ~500Mbps, maybe a little more, I don't recall.

With my 2018 mini, it was almost double.

When it happened with my SanDisk Extreme Pro (m.2 inside), I went looking for an answer.

I don't know why Apple doesn't support that particular protocol/standard.

It seems to be popular with external drives, and according to the innerwebs, it's a common standard in the PC world, so I'm curious about the why.

And the USB forum/consortium/whatever didn't do us any favors with changing the nomenclature of USB standards.

And the fact that a 'USB-C shaped' port may support some standards and not others depending on the given machine, doesn't help those of us who don't live, eat, and breath specs.

The lack of Apple support for this specific standard took a lot of people by surprise.

Anyway, I've got an empty MX2 enclosure which will work on all my Mac kit, albeit not particularly fast..

That'll do me until a good price on a USB4/TB4 (is there such a thing) box or boxes come along.

I'd like to see 3000-3500Mbps my 8200, but I don't know that will ever happen.

All the reviews I've seen on it and Samsung Pro sticks that get that kind of speed have been done on PCs.

One review said 'you can expect a little slower speeds on a Mac'.

Oh, thanks so much.

[Robert M]

RAM,

"It surprised me when I tried my XPG 8200 with my M1 MBA"

I find this telling. Those speeds with an NVME stick in a USB 3.1 Gen 2 box are within the same general range of a 2.5" SATA SSD in a similarly equipped box. The difference is you can take the NVME stick out of the USB 3.1 Gen 2 box and plant it into a USB 3.2 or Thunderbolt box and enjoy a significant improvement in performance. No can do with the 2.5" SSD. Swapping the box ain't gonna make a difference. It'll still be a drive that is in the 500Mbps to 550Mbps (or so) range.

Since I'm considering a move to an M1 box at some point, I'm looking at moving my 1TB NVME sticks from their current USB 3.1 Gen 2 boxes to Thunderbolt boxes. I heard that if you want to use an external drive as a boot drive, a Thunderbolt external is the way to do it. So, I'd benefit from the boost in speeds with the existing hardware and be ready to go for the M1 machine once I jump to it.

Robert

[pqrst]

Not super surprised. For a long time, on my MacBook pros, only one port or two was full on usb 2 or 3 (depending on what model it was). And what was cutting edge at the time. A Genius Bar person told me that her theory was that having an older slower chip was a way of making sure that they supported older equipment. Who knows.

[Filliam H. Muffman]

The M1 Max Studio doesn't have Thundercrap 4 ports on the front because the 10 core version only has one controller. You need to get the M1 Ultra Studio 20 core version to get front and rear Thundercrap 4.