So what is all this then about cables? As previous posts have shown the differences between USB C as a connector type and what runs on it are super confusing. But the essential points when buying cables are to realize the data protocols are completely separate from the amount of power delivered, so the relevant specifications are:
- Thunderbolt 4 remains the highest standard, a cable that can handle Thunderbolt 4 can take data from everything else including Thunderbolt 3, USB 4.0, USB 3.2, USB 3.1, USB 2.0, and DisplayPort. This is a 40Gbps specification (USB 4.0 can now match at 1 meter while Thunderbolt runs at 1 meter and up to 2 meters with power).
- Thunderbolt 3 cables are identical to Thunderbolt 4. The main difference is actually in the controllers which now allow buses in addition to daisy chaining, so you can now have a Thunderbolt 4 hub or docking station and plug a bunch of Thunderbolt 3 or 4 devices in parallel rather than in series. And Thunderbolt 3 uses a less powerful version of DisplayPort 1.2, while Thunderbolt 4 has USB 4.0 which supports DisplayPort 2.0 alternate mode supporting 8K devices
- USB 4.0 Cables. These are a subset of Thunderbolt 3/4 with the limitations listed
USB Power Delivery (USB PD)
Completely separate from this are the USB Power Delivery specification and here there is a lot of confusion. You for instance can have a USB C cable that supports USB Power Delivery to 100W but only USB 2.0 at 480Mbps, so the two specifications are not correlated at all, but here are the Power Delivery levels:
There are many sorts of powering, but the things to know are:
- The power delivery relies on a chip inside the cable, so be sure to check Fakespot in particular for cables that are too cheap. At one time many of the cables did not work properly in supplying the right voltage so beware
- The typical power being supplied are 18W (2A x 9V) and 15W (3A x 5V)
- The other common ones are 60W (3A x 20V)
- Thunderbolt only supports PD up to 100W
- The latest PD is what is called extended power range (EPR) so power above 100W which is done by incrasing voltages to 28V, 36V and 48V so that 240W which is 48V x 5A so be on the lookout for those
The net recommendation get Thunderbolt 3/4
The basic recommendation after all this is that if you are completely confused, spend the extra dollars and get the 1M Thunderbolt Cables. Yes hey do not support the 240W USB PD latest regimes, but they will go to 100W and you can be sure they will work for other things. They do cost a fortune though, so in this era, the only solution is to buy a variety and then label them appropriately so you do not make the mistake of thinking you are getting 5Gbps when you have a USB C cable that is 100W for USB PD but only support USB 2.0 480Mbps speeds. You are warned 🙂
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