Ookla’s C1X report’s most shocking result? People are buying iPhone Air

Cellular research and analysis company Ookla, owners of the very popular Speedtest app and site, has issued a fascinating report gleaned from Speedtest user data in the fourth quarter of 2025.

There are two key takeaways: The iPhone Air is more popular than other premium “slim” phone variants and the iPhone “Plus” models it replaced, and Apple’s C1X modem has made enough improvements over the C1 to be a fully “tier 1” modem, offering an overall equal alternative to Qualcomm’s X80 in most respects.

iPhone Air sales

While Apple’s C1X debuted in the iPhone Air, it has since appeared in a few iPads and now the iPhone 17e. Ookla’s data is from the 4th quarter of 2025 and focuses on smartphones, though. So all C1X results in this report are exclusively iPhone Air results.

While Ookla doesn’t have sales data, it collects speed results and hardware identifiers from millions of users, so it is generally true that the ratio of Speedtest results more or less correlates with sales ratios.

It appears to be especially popular in certain markets outside North America. Most of the results come from South Korea, Japan, and Singapore. Then Italy, Spain, and the UAE. North American markets are further down the list. But the most interesting chart is this one, comparing the iPhone 17 generation to the iPhone 16 generation.

Ookla

It shows an increase in base iPhone 17 results compared to iPhone 16 (as expected) and a reduction in iPhone 17 Pro samples. But the iPhone Air has double the samples of the iPhone 16 Plus that it replaced. Given that it costs $100 more, and no other segment saw such a dramatic swing in test samples, it’s safe to say that people were more excited to pay for a super-slim phone than a slightly larger one. Although in the U.K. the iPhone Air has been discounted since it went on sale, currently £200 off at Amazon, which may well explain the interest in the handset.

Ookla notes that it far outsells other competing premium slim phones. The Galaxy S25 Edge is behind, but competitive, in South Korea only. Elsewhere, it represents a tiny fraction of test results.

C1X makes big strides

Apple pitched the C1X modem as simply being “up to twice as fast” as the C1, which debuted about a year ago in the iPhone 16e. That sort of inexact and cherry-picking marketing promise is next to useless, but Ookla’s huge sample of test results gives us a good look at the improvements. And they are substantial.

Ookla primarily compared the chip to the standard Qualcomm X80, while noting that the more advanced X18 and the MediaTek X90 are giong to be common in Android flagship devices this year. It’s also worth noting that the C1X does not support mmWave frequencies (a feature which is not terribly important globally, and may be overrated in North America).

Ookla

The iPhone Air (C1X) is now essentially equal in performance to the iPhone 17 Pro Max (Qualcomm X80). And that’s true under rough conditions, great conditions, and average conditions. The iPhone 16e (C1) lagged behind considerably. This data is from the U.S., but the story is the same in every market Ookla measures. Apple has caught up.

This next chart is especially illuminating. It shows the improvement in latency (in milliseconds) for the iPhone Air vs the iPhone 16e (green) and the iPhone 17 Pro Max (blue).

Ookla

The C1X modem has a substantial and consistent advantage in latency compared to both the C1 and the Qualcomm X80. A couple of markets stand out as exceptions (notably South Korea and Taiwan), but it is clear that Apple has made a big leap in hardware and software integration.

The Ookla report has some other interesting findings, and is well worth a look. For example, performance at the “network edge” (the 10th percentile) has improved a lot. Qualcomm’s X80 still performs better here, but the C1X handles poor network conditions a lot better than the C1 did. The iPhone Air is able to get almost gigabit speeds in ideal conditions, where the C1 in the iPhone 16e seemed to hit a wall around 600Mbps in many markets. The upper ceiling for ideal network conditions is a lot higher in most markets for the C1X.

Ookla’s data paints a rosy picture for Apple’s cellular modems. The iPhone Air is a very challenging body in terms of thermal performance and antenna design, and the C1X has made big real-world strides compared to the C1. Assuming the C2 lands later this year with mmWave support for the iPhone 18 Pro, it could be a serious competitor to the Qualcomm X85, the current leading 5G platform.

If Apple can keep up the pace of innovation, you can have confidence that choosing an Apple product doesn’t mean settling for a second-best cellular connection.