Ookla has analyzed the real-world performance of Apple’s custom C1X modem in the iPhone Air, based on Speedtest Intelligence data from the last quarter of 2025.

Key takeaways include:

Apple’s in-house C1X modem represents a generational leap over the previous C1 model, achieving real-world parity in download and latency performance with the Qualcomm X80 across numerous networks.

The C1X led over the C1 in all the markets in this study in median download speeds. This was particularly apparent for the UAE, U.S., Saudi Arabia, China, Sweden, Singapore, and Japan.

The C1X shows significant upside vs. the C1 in more advanced 5G networks, including the UAE and Saudi Arabia.

The iPhone Air outperformed the Qualcomm-based iPhone 17 Pro Max in latency metrics across 19 of 22 analyzed markets.

In the UAE, the Air capitalizes on the fastest 5G market in the world, to deliver a +643.9 Mbps advantage over the 16e (1,832.3 Mbps vs. 1,188.4 Mbps).

In Saudi Arabia, the Air provides +362.8 Mbps more bandwidth (970.0 Mbps vs. 607.2 Mbps).

The Qualcomm X80-equipped iPhone 17 Pro Max maintained up to a 32% lead in upload speeds.

While Apple has achieved parity in download metrics, Qualcomm’s mature implementation of Uplink Carrier Aggregation (UL-CA) remains the industry benchmark.