Thunderbolt 4 or Thunderbolt 5 – which is it?

bob277 wrote:

Apple Support, <Identify your MacBook Pro model - Apple Support>, says my MacBook Pro (14-inch, M4 Pro, Nov 2024), Model Identifier Mac16,8, Part No. MX2J3LL/A, “includes three Thunderbolt 5 ports”, but my "System Report…" says they are Thunderbolt/USB4; which is it?

The System Information heading is a generic one. Thunderbolt/USB4 simply means that this is a place where you can see information pertaining to Thunderbolt, and/or pertaining to USB4 – if your Mac supports them.

The title does not indicate what version of Thunderbolt your Mac has. The '4' modifies USB. The official name of "version 4 of the USB standard" is USB4 – with no space between the "USB" and the "4". (I believe that there is, now, a USB4 version 2.0, just to make things more confusing!).

The title does not indicate that your Mac has Thunderbolt or has USB4. You will see the same title

• On Intel-based Macs. Those can have Thunderbolt 3, but none of them have Thunderbolt 4 or 5, or USB4.
• On Apple-Silicon-based Macs that have Thunderbolt 3, Thunderbolt 4, or Thunderbolt 5. I believe that all Apple Silicon Macs to date have USB4. The first Apple Silicon Macs were either the first, or among the first, computers from any manufacturer to implement the then-new USB4 standard. All Apple Silicon Macs have some version of Thunderbolt - but whether this is version 3, 4, or 5 depends on the particular model.

It might be nice if the report showed which Thunderbolt version you have, and whether you have USB4, but this is simply a case of an incomplete report – not of one that contradicts Apple's Technical Specifications.

How deeply do you want to dip into the pit of puzzlement?

USB-C is a connector standard, and various cables and various protocols can be supported. Or not supported. But again, USB-C is the connector, not what Thunderbolt or USB or power might be available on any host port.

Thunderbolt 5 is an implementation of USB4 V2.0, and USB4 includes Thunderbolt.

The marketeers got ahold of the naming: https://en.wikipedia.org/wiki/USB4

The USB-C cabling got complex, too: https://people.kernel.org/bleung/

Some other marketeers are trying to make this all less confusing: https://www.pcworld.com/article/2602229/better-usb-labels-are-finally-coming-heres-what-they-mean-for-you.html

As for what a particular Mac supports, that’s in the Mac tech specs, as cited in the various sage replies above.

What does  > About This Mac have to say about the identity - model, year and chip - of your MacBook Pro?

The 2024 MacBook Pro with M4 chip has Thunderbolt 4 ports.

MacBook Pro (14-inch, M4, 2024) - Tech Specs - Apple Support

The 2024 MacBook Pro with M4 Pro or M4 Max chip has Thunderbolt 5 ports.

MacBook Pro (14-inch, M4 Pro or M4 Max, 2024) - Tech Specs - Apple Support

ThunderBolt-5 can attain its higher rated speeds ONLY when connected to genuine ThunderBolt-5 peripherals, of which there are currently VERY few, and quite expensive.

ThunderBolt-5 does this speed increase by using a modulated signal to encode multiple bits in one signaling interval. if your connected peripheral is not also ThunderBolt-5, it will not understand multiple bits per signaling interval, and will not run at higher speed.

In all other cases, Thunderbolt-5 ports are backward-compatible to older versions of ThunderBolt and USB.

Grant Bennet-Alder wrote:

In all other cases, Thunderbolt-5 ports are backward-compatible to older versions of ThunderBolt and USB.

An article on the Other World Computing site indicates that the reverse is not true.

Thunderbolt 4 and 5 docks, drives, and other peripherals are not backwards compatible with Thunderbolt 1 and 2 hosts. The backwards compatibility is with hosts that have USB-C-based Thunderbolt ports.

If you have an old Mac with Thunderbolt 1 or 2 ports, and you're thinking about using an Apple Thunderbolt 3-to-2 adapter to let it access modern Thunderbolt devices, you must limit yourself to Thunderbolt 3 devices. (You must also ensure that the one directly connected to the adapter has its own power supply.)

so sorry. I stand corrected.

Thunderbolt-2 and -1 are a world apart, and getting so old, I tend to forget about them.