Thunderbolt 3 vs. Thunderbolt 4 cables: Do they have the same feature set?

[EugW]

Apple sells passive Thunderbolt 3 cables and active Thunderbolt 4 Pro cables.

Besides the length, are these functionally the same? Their listed specs appear identical.

Thunderbolt 3 USB‑C Cable 0.8 m - Apple

Apple Store Search Results

www.apple.com

Thunderbolt 4 (USB-C) Pro Cable (1.8 m)

Thunderbolt 4 Pro Cable provides superfast data transfer, charging, and connection to your compatible Mac. The braided design avoids tangles. Buy now.

www.apple.com

 

[zorinlynx]

I can say with absolute certainty that they're NOT the same. I have a Studio Display and had a 0.8M TB3 cable, the same one you listed above, laying around, so I tried using it instead of the cable that came with it (the TB4 pro cable) so I'd have a longer cable for other tasks, and it DID NOT work. No image, nothing.

So I went back to the cable that came with the ASD.

The 0.8m cable I have does work; I've used it for data transfers between Macs. But it definitely lacks features in the TB4 Pro cable that at least the ASD needs.

 

[EugW]

I can say with absolute certainty that they're NOT the same. I have a Studio Display and had a 0.8M TB3 cable, the same one you listed above, laying around, so I tried using it instead of the cable that came with it (the TB4 pro cable) so I'd have a longer cable for other tasks, and it DID NOT work. No image, nothing.

So I went back to the cable that came with the ASD.

The 0.8m cable I have does work; I've used it for data transfers between Macs. But it definitely lacks features in the TB4 Pro cable that at least the ASD needs.

Hmmm... That's interesting. I wonder what the difference is. I now notice in the specs that the Studio Display is not listed as supported for the Thunderbolt 3 cable.

I wonder what would happen with a third party certified Thunderbolt 4 cable.

 

[entwerfen]

I had the exact opposite experience. I purchased a Mac Studio and Studio Display. The display wouldn’t work, while my old Thunderbolt Display worked fine. Before returning the monitor, I picked up an Apple Thunderbolt 3 cable (1.5m), and replaced the cable from the Studio display - it worked fine. That was a couple months ago, I don’t know if the specs are different, but it works for me.

 

[BeatCrazy]

Hmmm... That's interesting. I wonder what the difference is. I now notice in the specs that the Studio Display is not listed as supported for the Thunderbolt 3 cable.

I wonder what would happen with a third party certified Thunderbolt 4 cable.

I'm going to plagiarize a bit, because this comment covers it:

The real reason to get TB4 cables over TB3 cables is if you’re in the market for >0.8m cables. TB4 cables at those lengths will also support fast USB data rates, which pure TB3 cables cannot do because their circuitry (the thing that makes the cable “active”, required for length >0.8m) only supported specific TB signaling rates that are different from what it is required for USB 3.1 or 3.2, let alone 4 (and in fact even DP alt mode). TB4 cables support all signaling rates and hence are what you want to pick if (and probably only if) you need a longer cable. CalDigit and CableMatters both sell such 2.0-m long TB4 cables.

Should you switch to Thunderbolt 4 cables?

Although little more expensive than good Thunderbolt 3 cables, what are the differences in Thunderbolt 4? When do you need a new TB4 cable?

eclecticlight.co

 

[EugW]

I had the exact opposite experience. I purchased a Mac Studio and Studio Display. The display wouldn’t work, while my old Thunderbolt Display worked fine. Before returning the monitor, I picked up an Apple Thunderbolt 3 cable (1.5m), and replaced the cable from the Studio display - it worked fine. That was a couple months ago, I don’t know if the specs are different, but it works for me.

At 1.5 m, @BeatCrazy's post suggests that the cable you bought was active, not a passive Thunderbolt 3 cable.

I'm going to plagiarize a bit, because this comment covers it:

The real reason to get TB4 cables over TB3 cables is if you’re in the market for >0.8m cables. TB4 cables at those lengths will also support fast USB data rates, which pure TB3 cables cannot do because their circuitry (the thing that makes the cable “active”, required for length >0.8m) only supported specific TB signaling rates that are different from what it is required for USB 3.1 or 3.2, let alone 4 (and in fact even DP alt mode). TB4 cables support all signaling rates and hence are what you want to pick if (and probably only if) you need a longer cable. CalDigit and CableMatters both sell such 2.0-m long TB4 cables.

Should you switch to Thunderbolt 4 cables?

Although little more expensive than good Thunderbolt 3 cables, what are the differences in Thunderbolt 4? When do you need a new TB4 cable?

eclecticlight.co

 

[BeatCrazy]

At 1.5 m, @BeatCrazy's post suggests that the cable you bought was active, not a passive Thunderbolt 3 cable.

However... even an 'active' TB3 cable is not the same as TB4 cable. A >0.8m TB3 cable must be active to support higher-speed USB, but then it loses backwards compatibility for data transfer with non-TB devices.

So while you can get 10Gbps USB speeds between two non-TB devices with a 1.5m TB4 cable, you cannot get that USB performance from an active 1.5m TB3 cable.

 

[EugW]

However... even an 'active' TB3 cable is not the same as TB4 cable. A >0.8m TB3 cable must be active to support higher-speed USB, but then it loses backwards compatibility for data transfer with non-TB devices.

So while you can get 10Gbps USB speeds between two non-TB devices with a 1.5m TB4 cable, you cannot get that USB performance from an active 1.5m TB3 cable.

Hmmm... Good to know. This is a lot more complicated than I expected.

I'm going to buy a passive USB4 40 Gbps cable. Spigen makes a USB-IF certified 2.6 foot / 80 cm USB4 40 Gbps cable that's currently on sale so I'll get that. Interestingly, I see that two well-respected brands, Plugable and Club 3D, that both make supposedly USB-IF certified 40 Gbps USB4 cables that are 3.2 feet and 3.28 feet respectively, and I believe they are both passive, at least judging by the pricing.

I think I'll just get the 80 cm Spigen one. Truthfully I don't need a USB4 capable cable right now since I'll just be using it with a USB-C 3840x2560 (3:2) Huawei MateView monitor, but I figure that since I already have a USB4 / Thunderbolt 4 hub, I may as well get the proper cables to support that too.

 

[Shazaam!]

OWC now sells three Thunderbolt 4 cable lengths for $24, $34, and $57—far less than Apple’s $129 entry.