Apple has been working for many years on developing its own mobile data modem to replace the Qualcomm ones on which it has traditionally relied. The first of these, the C1 chip, was used in the iPhone 16e, and is also expected to be used in the upcoming iPhone 17 Air.
There have so far been mixed messages on how well it compares to Qualcomm’s current chip, and a new study by Ookla provides our most detailed comparison yet …
Ookla’s speed tests
If you’ve ever tested your home or mobile broadband speed, there’s a high chance you’ve done so using Ookla’s Speedtest.net. In addition to displaying the speed to you, the company logs the results of all those tests – together with the devices and networks used – to create a comprehensive picture of the speeds offered by each.
For example, by comparing networks, Ookla was able to see that T-Mobile offered the fastest mobile data, while AT&T was best for broadband.
Comparing the performance achieved by the iPhone 16, which uses Qualcomm’s chip, with the iPhone 16e, which uses Apple’s own C1 chip, the company was see how each modem fared.
A mixed picture had so far emerged
Ookla’s first study, published back in March, showed that the C1 chip beat Qualcomm in a number of key areas. That one showed that the C1 was better in areas of poor mobile coverage, but Qualcomm came out significantly ahead when it came to the areas with the fastest connections.
A subsequent report put Qualcomm further ahead, but the fact that it was paid for by the company clearly raised questions as to the reliability of the data.
Here’s what the latest study says
Performance doesn’t just depend on the chip, but also on the network on which it is used. That’s because different networks support different chip features, as noted in Ookla’s latest study.
For example, carrier aggregation is a technique used to combine different frequencies into a single mobile data connection so as to maximise the total bandwidth achieved. Qualcomm supports aggregation across four carriers, while the C1 modem only supports three. So if you’re on T-Mobile, then having a Qualcomm modem is an advantage.
In the U.S., T-Mobile users experienced better performance on the iPhone 16, which supports four-carrier aggregation, than iPhone 16e users with the Apple C1 modem, which supports a maximum of three-carrier aggregation. Median download speed for the iPhone 16 on T-Mobile’s network was 317.64 Mbps, compared to 252.80 Mbps on the iPhone 16e. Ookla RootMetrics controlled testing in the US during 1H 2025 showed that T-Mobile’s network used four-carrier aggregation across 65.4% of locations tested, giving the iPhone 16 a distinct advantage on its network.
Looking at the international picture, Ookla found that the iPhone 16 performed better than the 16e in countries with the most advanced 5G networks, notably China and Saudi Arabia. In most countries, however, the two offered very similar speeds.
The study also underlined better performance of the C1 when it came to poorer connections, suggesting that Apple may have optimized for reliability over ultimate speed.
If you’re considering buying the iPhone 17 Air, do these latest results give you any pause? Please share your thoughts in the comments.
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