How can I tell if all USB-C ports on a 2020 M1 MacBook Pro are the same speed, or if one or more will be faster than others?

I'm doing some heavy copying of files, and wish to do it via the fastest USB-C connection possible.

I tried holding option and clicking on the apple logo on the very top left, then going to System Information. From here on I'm guessing. I looked under 'Hardware' and see two areas of interest: 'Thunderbolt/USB4', and 'USB'. Does this automatically imply that one or more USB-C ports are faster than others?

Question

How exactly can I tell if one (or more) USB-C ports on a MacBook Pro offers faster speeds, and how can I easily know which that is?

Apple Menu, "About this Mac", "System Report", "Hardware", "USB" and you get a list of all USB devices connected with their speeds. If a device is not connected directly but through a hub, that will cause a little bit of time. If multiple devices are connected to the same hub, they will have to share the bandwidth - they will slow down if they are used simultaneously.

And one trap that might be misleading you: If a hub has only slow devices connected, then it will often report that it has the slow speed itself. So a USB 3 hub with only USB 2 devices plugged in may report that it is a USB 2 hub itself; plug in a USB 3 device and it changes to a USB 3 hub.

Apart from the technical specifications which are the same for all ports on the M1 device you own (because USB-4 currently is M1 only on Apple), you could try Blackmagic Disk Speed test to test the actual speeds.

As Mr R mentioned in the comments the ports on this device usually allow for much greater transfer speeds than what your media will support. HDDs usually write/read at about 200 MB/s and depending on the SSD model you can reach GB speeds. Modern M.2 NVMe SSDs can actually exceed the 5GB/s speeds port limit, yet at that point you don't only need a very capable SSD and enclosure, but also your M1 Mac needs to handle these speeds. E.g. the internal M1 SSD maxes out at roughly 3GB/s.

I assume you have a 2020 model year MacBook Pro with the M1 chip. Your Mac has two USB C ports. Both support USB4, which according to Apple can achieve speeds up to 40 Gb/s. AFAIK there are no USB4 drives yet available for purchase. Thunderbolt 3 drives will work with your Mac and also operate as speeds up to 40 Gb/s, but Thunderbolt 3 drives are not compatible with USB 3.2 or previous versions of USB. There exists USB 3.2 Gen 2x2 drives, which operate at speeds up to 20 Gb/s. However, Apple specifications for your Mac do not mention USB 3.2 Gen 2x2 support. Apple's specifications for your Mac does show support for USB 3.1 Gen 2 (up to 10 Gb/s). This is also known as USB 3.2 Gen 2x1. An example of a USB 3.2 Gen 2x1 drive would be the Samsung T7 Portable SSD. This drive is backward compatible all the way to USB 1.1 and comes with USB type C and A cables.

User X_841 posted in a comment to another answer that the "M1 SSD ... won't be faster than 3GB/s." If this is true, then you might consider a Thunderbolt 3 drive such as the Samsung X5, which has a read/write speeds of 2.8/2.3 GB/s and supports TRIM. Thunderbolt 3 is compatible with the newest Macs and many newer PC's. Be aware that you can not connect a Samsung X5 to an older Mac with Thunderbolt 1 or 2 though Apple's Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter. The reason is that the drive is not self powered and the adapter can not provide power.