Apple might make you pay extra for one of the iPhone 15 Pro's biggest upgrades

iPhone 14 Pro and Pro Max on pink background
(Image credit: Future / Apple)

We’ve long suspected that Apple’s adoption of the USB-C standard on the iPhone 15 Pro will bring tangible improvements to data transfer speed, but tipsters have remained divided over just how fast these speeds might be.

Now, we’re hearing that Apple could be preparing to release an optional USB-C data transfer accessory cable for the iPhone 15 Pro and iPhone 15 Pro Max – one that’s capable of Thunderbolt or USB4 data transfer speeds of up to 40Gbps.

This tip comes from serial Apple leaker Kosutami, who claims (via X) that this Thunderbolt cable will measure 0.8m and support charging up to 150W (Kosutami initially mentions 120W, but the leaker has subsequently corrected this figure in a follow-up post).

That’s not to say the iPhone 15 Pro and iPhone 15 Pro Max will be capable of charging up to 150W, mind – the latest intelligence suggests that Apple’s top iPhone 15 models will offer 35W charging at best – but this latest tip does corroborate existing rumors surrounding improved maximum data transfer speeds for these devices.

Apple analyst Ming-Chi Kuo, for instance, has previously suggested that Apple’s iPhone 15 Pro models will ship with cables that support “at least” USB 3.2 or Thunderbolt 3. “This spec upgrade means the wired transfer and video output user experience [on the iPhone 15 Pro and iPhone 15 Pro Max] will significantly improve,” Kuo claimed via X in November last year.

Support for USB 3.2 or Thunderbolt 3 on the iPhone 15 Pro and iPhone 15 Pro Max would allow for data transfer speeds of up to 20Gbps – that’s already significantly faster than the 480Mbps maximum transfer rate offered by the current best iPhones.

Kosutami’s post, however, teases the potential existence of an optional, not-in-the-box cable that – being based on the Thunderbolt 4 protocol – would facilitate even faster data transfer speeds of up to 40Gbps (double that of Thunderbolt 3). Presumably, then, you may have to fork out extra money to get the best out of your iPhone 15 Pro or iPhone 15 Pro Max.

In any case, the data transfer speeds offered by the iPhone 15 Pro and iPhone 15 Pro Max are all but certain to dwarf the equivalent figures offered by their iPhone 15 and iPhone 15 Plus siblings. The latest rumors suggest that the cables supplied alongside those iPhones will be limited to the USB 2.0 standard – in other words, they’ll offer the same 480Mbps maximum transfer speeds as Apple’s existing Lightning cables.

For a speculative look at more of the key differences between Apple's upcoming iPhones, check out our comparative piece on the iPhone 15 vs iPhone 15 Pro.

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Axel Metz
Phones Editor

Axel is TechRadar's UK-based Phones Editor, reporting on everything from the latest Apple developments to newest AI breakthroughs as part of the site's Mobile Computing vertical. Having previously written for publications including Esquire and FourFourTwo, Axel is well-versed in the applications of technology beyond the desktop, and his coverage extends from general reporting and analysis to in-depth interviews and opinion.  Axel studied for a degree in English Literature at the University of Warwick before joining TechRadar in 2020, where he then earned an NCTJ qualification as part of the company’s inaugural digital training scheme.