Apple’s M1 Mac Thunderbolt4 has caused dissatisfaction. According to 9to5Mac, citing professional user reports, Apple’s M1 Mac’s external SSD transfer rate is very disappointing. And mentioned that there are problems with several models, including the 2021 16-inch MacBook Pro (M1 Pro) and the 2022 Mac Studio (M1 Max), neither of which support USB 3.1 Gen 2 well – which would mean They have difficulty achieving 10Gbps data transfer.
Many people are dissatisfied with this situation, and users have repeatedly criticized the confusion caused by different USB-C standards, devices, and cables, especially between the theoretical and measured maximum transfer rates. significant difference.
In this regard, Eclectic Light also pointed out: USB 3.0 (SuperSpeed) supports 5 Gb/s, while USB 3.1 Gen 2 (SuperSpeed+) supports 10 Gb/s, and USB 3.2 (SuperSpeed+) maintains 10 Gb/s, the highest It is USB 3.2 Gen 2×2 supporting 20 Gb/s. However, after Howard Oakley tested the Thunderbolt4 ports of two M1 Macs, he found that the so-called speed specification has shrunk.
One of them is a Mac Studio (M1 Max model) equipped with 32GB RAM + 2TB built-in SSD, which is connected to the Studio Display together. In addition, the 16-inch MacBook Pro (M1 Pro model) is also equipped with 32GB RAM + 2TB built-in SSD, and uses the internal screen to display.
First, Oakley did a pre-test with an Intel Mac (connected to a 10 Gb/s port) to prove that there were no compatibility issues with the SSD and USB cables on hand. The cable model covers the certified Thunderbolt4 version, as well as the supplied USB-C data cable, and is judged by the USB speed given in the system.
Then, the free Stibium 1.0 (55) is included in the actual SSD speed measurement software. First, 160 files ranging in size from 2MB to 2GB are written into a folder on the SSD, and then these files are read back to evaluate The read and write speed of the device.
When Oakley compared the performance of SSDs on Intel / M1 Macs again, as expected, the measured performance on the new Apple Silicon machine was indeed low.
According to Oakley, the issue is mainly due to the fact that the external solid-state storage is only running about half as fast as expected, and it’s worth mentioning that this limitation seems to be pervasive on all M1 Macs, which means it can’t be used at full speed.
However, when using a Thunderbolt 4 cable and connecting a USB-C device to the front port on the Mac Studio (M1 Max), the measured speed is slightly different, but only 10% slower than expected. And at 9to5Mac’s Ben Lovejoy, the issue has been that since November 2020 the 10 Gbps Thunderbolt port on any M1 device has been unable to perform as expected (at least for SSDs).
That is to say, even if users use the latest Mac Studio, USB 3.2 Gen 2 is not supported. The relatively better performance is currently only the front port on the Mac Studio (M1 Max).
In summary, the impact is greater for users who often use SATA / USB-C external storage to perform Time Machine backups, and the performance impact is relatively limited – probably at the expected 500 MB/s transfer rate , down to around 400 MB/s.
However, this is generally only the case when the transfer rate is close to 10 Gbs – and with a RAID array with USB 3.1 Gen 2 (rather than Thunderbolt3), or an NVMe SSD – the expected 900 MB/s transfer rate is cut in half At 500 MB/s this result will also double the time required for reads and writes.
For this problem, there are currently two main guesses: First, if Apple actually knew that the problem was caused by a bug in the Fabric core firmware, why wasn’t it fixed a year ago. Second, if the M1-series processors are an issue, the company should have notified users of the compatibility flaws in these ports for so long.
As a final note, if you’re using the M1 Mac unit released in the last year and a half and don’t want to be held back by this issue, the best thing you can do right now is through a Thunderbolt3 dock (or the USB Hub port on the Studio Display) to avoid.