Ookla has published a report analyzing the real-world performance of Apple’s custom C1X modem, introduced with the iPhone Air. Using global Speedtest data, the study shows that Apple’s in-house modem has reached a new level of maturity, achieving near parity with Qualcomm in download performance while delivering consistent improvements in latency.
The iPhone Air also reflects a broader shift in Apple’s product strategy. The iPhone 17 lineup now includes six models, with the Air replacing the Plus variant as a slimmer, design-focused option.
Adoption trends show regional divide
The rollout of the iPhone Air highlights a clear split between design-focused buyers and performance-driven users. Markets that prioritize portability and form factor have responded more positively, while price-sensitive regions show slower adoption.
Leading markets:
- South Korea – 11.2%
- Japan – 8.9%
- Singapore – 8.4%
Moderate uptake:
- Sweden – 8.6%
- Italy – 7.7%
- UK – 6.5%
In Europe, adoption is also influenced by contract upgrade cycles and carrier promotions, which tend to favor established models over newer variants.
India: limited gains despite modem improvements
India is among the markets where the iPhone Air has seen lower adoption and limited performance gains from the C1X modem.
Key observations:
- Lower adoption compared to leading markets
- Minimal median download improvement vs C1
- Upload variance of around -5.2 Mbps compared to X80
These results reflect local network conditions, including congestion and deployment differences, which reduce the impact of modem improvements.
U.S. market: Air strengthens mid-tier position
In the United States, the iPhone Air accounts for 6.8% of the installed base, more than doubling the 2.9% share of the Plus model it replaces.
Lineup shift:
- iPhone 16 Plus – 2.9%
- iPhone Air – 6.8%
Model share movement:
- iPhone 17 Pro Max – ~55.5% (stable)
- iPhone 17 Pro – 34.9% → 30.6%
- Base model – 5.9% → 7.0%
The data indicates that the Air draws users primarily from the Pro segment, while Pro Max demand remains stable.
Slim segment: Apple leads over Samsung
Apple’s slim flagship approach has outperformed the Samsung Galaxy S25 Edge in most markets.
Comparison:
- U.S. – Air 6.8% vs 2.4%
- Europe – Samsung model below 1% in key regions
- South Korea – Air 11.2% vs 8.7%
This shows stronger global traction for Apple’s slim premium positioning.
C1X modem: improvements in everyday performance
The C1X modem delivers a clear improvement over the previous C1, particularly in typical usage conditions. Despite the slim design, the iPhone Air uses a vapor chamber and titanium frame to manage heat and maintain performance.
Median performance reflects better efficiency on mid-band 5G networks and improved handling of congestion.
Strong gains observed in:
- UAE
- United States
- Saudi Arabia
- China
- Sweden
- Singapore
- Japan
Limited gains in:
- India
- Brazil
- Malaysia
Compared to Qualcomm’s X80 modem, performance is now closely matched in most real-world scenarios.
Upload and latency: key improvements
Upload performance sees consistent gains, improving tasks such as file sharing and cloud usage.
Typical upload improvement:
- Around +5 to 10 Mbps
Latency is the strongest area of improvement, improving responsiveness across applications.
Latency improvements:
- China – ~6 ms lower
- Indonesia – ~6 ms lower
- United States – ~5 ms lower
Overall results:
- Lower latency in 18/22 markets vs C1
- Lower latency in 19/22 markets vs X80
Weak signal performance improves reliability
Under poor signal conditions, the C1X modem reduces performance drops and improves usability.
Upload gains in weak signal:
- Singapore – +4.3 Mbps
- China – +1.3 Mbps
- United States – +1.0 Mbps
The modem also performs better in markets with advanced 5G deployments, including 5G Standalone and 5G Advanced networks.
Peak performance reaches near gigabit speeds
In optimal conditions, the C1X modem delivers significantly higher throughput compared to the previous generation.
Top-end gains:
- UAE – +643.9 Mbps
- Saudi Arabia – +362.8 Mbps
- United States – +264.4 Mbps
While Qualcomm’s X80 maintains an advantage in some scenarios, the overall gap is now minimal and influenced by network conditions.
A key difference remains in upload carrier aggregation, where Qualcomm retains an edge. However, Apple has narrowed this gap significantly.
At peak levels, the distinction between the two approaches shifts from raw speed to spectral efficiency, with Qualcomm offering broader consistency and Apple focusing on optimized performance in specific bands.
Outlook
The report from Ookla shows that Apple’s modem strategy has reached a significant milestone. The C1X modem delivers near parity with Qualcomm in download performance while improving latency and responsiveness.
Future improvements are expected in uplink carrier aggregation and efficiency, particularly with the next-generation C2 modem. At the same time, competition will continue with upcoming solutions such as Qualcomm X85, X105, and MediaTek M90.
Beyond smartphones, Apple’s modem roadmap could extend to its wider ecosystem. Integration into devices like MacBooks may enable always-connected computing, reducing reliance on Wi-Fi and expanding mobile connectivity across platforms.