What’s the Difference Between USB-C and Thunderbolt (and Why It Matters for the iPhone 15)

What’s the Difference Between USB-C and Thunderbolt (and Why It Matters for the iPhone 15)

USB-C is a wonder cable. Capable of transferring up to 240W of power (enough to power and recharge a gaming laptop), the port has been adopted on a wide range of consumer electronics, with the iPhone 15 expected to soon adopt it. However, while USB-C is brilliant, many users aren’t entirely clear what the difference is to one of its relatives – Thunderbolt.

This matters because, although the ports are similar, they’re not exclusively the same, and knowing which port is which may encourage you to rearrange how you have your cables plugged in. And with the iPhone 15 range rumoured to be adopting a Thunderbolt port instead of simply a USB-C port (at least for the Pro and Pro Max), it’s time that we get familiar with the difference.

Is USB-C the same as Thunderbolt?

USB-C and Thunderbolt ports are capable of using the same cables, but Thunderbolt is more powerful for data transfer when using a Thunderbolt-specific cable. Because the plugs and ports are the same between the two technology types, you can use a USB-C cable from, say, your laptop or your phone, and plug it into a Thunderbolt port, but you will only get the data transfer benefits of Thunderbolt when using a Thunderbolt-certified cable.

Intel, the creators of the Thunderbolt port (in collaboration with Apple), claim that it is capable of transferring up to 40 Gbps – that’s the entire file size of Starfield in about 30 seconds, and is about double the file transferring speed of standard USB-C 3. Additionally, Thunderbolt can project from a computer to an 8K display or two 4K displays, while USB-C 3 can only run up to two 4K monitors, though USB-C 4 is expected to catch up, with support for 8K and 16K displays and similar data transferring speeds.

There isn’t a difference when it comes to charging speeds. As both ports comply with Power Delivery standards, a smart way for devices that allows chargers and devices to recognise each other to get the highest wattage possible, USB-C and Thunderbolt transferring speeds are capped off at the maximum serviceable wattage of Power Delivery. At the moment, that’s about 100W for most consumer electronics, which is more than enough for a phone or casual use laptop without a graphics card, but can be bumped up to 240W. This higher wattage, however, is dependent on the existence of cables capable of transferring these higher wattages.

So why is Thunderbolt a big deal for the iPhone 15?

For professional photographers and phone power users who rely on fast data transfers, Thunderbolt could speed things way up. While lightning can reportedly transfer data at a maximum speed of 480Mbps, cables using the USB-C plug can transfer data at 10Gbps (that’s more than 20x faster). When we introduce Thunderbolt, that becomes about 100x faster.

So if you’re constantly moving massive files from your phone to your computer, you’re likely to see a substantial speed increase. We’re likely to see a bump in charging speeds with the iPhone 15, no doubt, as the technology switches from the slower Lightning port, but the real difference will be data transfer.

How do I tell if a port or cable is USB-C or Thunderbolt?

Any device that has the USB-C port is USB-C compatible – that’s easy – it’s just telling what a Thunderbolt port is that’s a bit difficult. Typically, when a laptop or device is Thunderbolt-compliant, it will have a Thunderbolt symbol beside or above it (often with a ‘3’ or ‘4’ to indicate which generation of Thunderbolt it belongs to), like what we’ve got in the image below, but this is not broadly true. Microsoft, for example, fitted the Surface Laptop Studio with two Thunderbolt 4 ports, although there is no symbol on the device indicating that these are Thunderbolt-compliant. Apple did the same thing with the recent iPad Pro.

USB-C ports beside a Thunderbolt 4 port. Image: Thunderbolt Technologies/Intel

Typically, you can check the device’s technical specifications online for if the port is, in fact, Thunderbolt-compliant, and if it is, it will say either ‘Thunderbolt 3’ or ‘Thunderbolt 4’. If it isn’t, it’ll likely be just USB-C 3.

And that’s really the big difference between these two technology types. Let’s hope the iPhone 15 ships with Thunderbolt, and not just USB-C.

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