A few days ago, specialists from the blog The Eclectic Light Company highlighted the poor performance of the Thunderbolt 4 port on Apple silicon Macs for USB-C 3.1 Gen2 devices.
If we were unable to take measurements ourselves, not having the necessary equipment, we were able to count on the work of Atelier 440, a Parisian music school equipped with Mac minis and in particular Mac mini M1s. We had access to data from their recent analysis done with several Mac mini, M1, Intel 2018 and Intel 20012, and two external hard drives, oneSamsung T7 (USB)and aSamsung X5 (Thunderbolt). And the results shown by this new survey are hardly encouraging. They indeed confirm what we feared.
Samsung T7 external drive (USB to Thunderbolt 3/4)
TheSamsung T7is an external SSD, NVME, supportingUSB 3.1 Gen2. The version of this device tested here is the one with 2 TB of storage. Here are the speeds obtained from a Mac mini M1 via the latter's Thunderbolt 4 socket and from a 2018 Mac mini Intel via its Thunderbolt 3 socket. Remember that both Thunderbolt 3 and 4 sockets are announced as USB 3.1 Gen2 compatible up to 10 Gb/s:
(Speed tests were carried out using Blackmagic Disk Speed Test software,available for free on the App Store)
- Mac mini M1 :722 MB/s write, 692 MB/s read
- Mac mini Intel :844 MB/s write, 916 MB/s read
Mac mini M1 records write throughput15% slowerthan the Mac mini Intel. In reading, the drop is even more striking:-24 %…
Samsung X5 external drive (Thunderbolt)
TheSamsung X5is an external NVME SSD that connects via Thunderbolt and supports version 3 of this connection. The model tested here is the one with 2 TB of storage, like the T7. Here are the speeds obtained in reading and writing with the measurement software, once again, on Mac mini M1 via its Thunderbolt 4 socket (backwards compatible with Thunderbolt 3) and on Mac mini Intel via Thunderbolt 3:
- Mac mini M1 :2,166 MB/s write, 2,546 MB/s read
- Mac mini Intel :2,150 MB/s write, 2,314 MB/s read
No big change to note between the two Macs here in writing (difference of 0.74%). In reading, the Mac mini M1 takes the advantage (throughput increased by 9%).
© Atelier 440
Thunderbolt 4 not friends with USB-C
In the end, we realize that the Thunderbolt 4 of the Mac mini M1 has a problem with USB. It cannot achieve the performance of USB 3.1 Gen2 via USB-C/Thunderbolt 3 port on Mac mini Intel. While, as specified above, the two versions of the connection are announced by Appleas supporting USB 3.1 Gen2 up to 10 Gb/s. In fact, we see it with this test and the data from the previous article obtained on Mac Studio as well, theThunderbolt 4 does not reach the expected level.
We are still thinking, with more and more supporting evidence, that Thunderbolt 4 on Mac with Apple silicon chip limits speeds when used with a USB-C 3.2 Gen2 device.
This is a point to know if you have acquired a machine with an M1, M1 Max, M1 Pro or even M1 Ultra chip, or if you are considering doing so. For external storage, and if speeds are important to you and your work, it is better to choose a Thunderbolt device rather than USB-C. It also seems that using a Thunderbolt 3 dock (with USB-C 3.1 Gen2 connectors) connected to the Mac would provide better performance for an external USB device than if the latter were linked directly to the computer via Thunderbolt 4 …
Many thanks once again to theAtelier 440, the school of contemporary music, for sharing their measurements.
Editor-in-chief for iPhon.fr. Pierre is like Indiana Jones, looking for the lost iOS trick. Also a long-time Mac user, Apple devices hold no secrets for him. Contact: pierre[a]iphon.fr.
