Apple’s C-Series Modems Show Real Progress Against Qualcomm in 5G Tests

Apple’s latest modem showdown shows how far its custom silicon strategy has come. In a recent comparison by YouTuber Stetson Doggett, four iPhones using different modems, the Apple C1, Apple C1X, Qualcomm X71, and Qualcomm X80 were tested on T-Mobile’s 5G and LTE networks. The results show that while Qualcomm’s chips still hit the highest peak speeds, Apple’s C-series modems deliver steadier performance and better power efficiency.



Speed on T-Mobile’s 5G Ultra Capacity



Across five consecutive 5G Ultra Capacity tests, results varied more between runs than between chips on the same network. That variation highlights how much conditions on the ground shape real speeds. Even so, Apple’s latest designs proved highly competitive.




Apple C1 (iPhone 16E): 1,135 Mbps down, 114 Mbps up.



Apple C1X (iPhone Air): 1,374 Mbps down, 101 Mbps up.



Qualcomm X71 (iPhone 16 Pro): 1,297 Mbps down, 93 Mbps up.



Qualcomm X80 (iPhone 17 Pro Max): 1,457 Mbps down, 120 Mbps up.





https://www.youtube.com/watch?v=5Nbjs-tm8ms




Despite Qualcomm’s X80 topping out at the fastest raw speeds, Apple’s C1X impressed with smoother averages. The iPhone Air showed smaller drops between runs, which helps you more than a single record spike. That pattern favors real use over one-off highs.



Average Speeds Tell a Different Story



When you average multiple tests, Apple’s C1X outpaced Qualcomm’s flagship in some runs. The iPhone Air landed near 1,216 Mbps on average, while the iPhone 17 Pro Max averaged about 875 Mbps in one set. That gap likely reflects tower congestion, time of day, and T-Mobile’s balancing, not only hardware differences.



Following behind were the iPhone 16 with Apple’s C1 at about 1,028 Mbps and the iPhone 16 Pro with Qualcomm’s X71 near 940 Mbps. Apple’s first in-house modems already trade blows with seasoned Qualcomm parts. That milestone matters for Apple’s modem roadmap and for your day-to-day consistency.



LTE and Weak Signal Results







LTE told a different story. The iPhone 16 Pro’s X71 led with 300 Mbps peak, followed by Apple’s C1 at 244 Mbps. The iPhone 17 Pro Max’s X80 averaged 236 Mbps. The spread looks small, but it suggests Qualcomm still holds an edge on legacy networks. You feel that edge when 5G coverage drops to LTE.



In weaker signal areas, the X80 stayed strong, averaging 96 Mbps down and holding a stable connection on T-Mobile’s N41 band. The C1X held near 70 Mbps, while older modems fluctuated. A modem that clings to a usable 5G link in fringe zones keeps your apps responsive when it counts.



Power Efficiency and Real-World Impact



The most compelling figure is Apple’s claim that C1X uses 30 percent less power than Qualcomm’s X71 at similar performance. Lower modem power use extends battery life, especially when your phone hunts for signal. That change benefits you on long days, in crowded venues, and on commutes across patchy coverage.



Apple appears to optimize for stability and endurance rather than headline bursts. Tight integration with iOS lets Apple coordinate connectivity, battery, and thermal behavior. Qualcomm still leads in raw throughput in ideal conditions. Apple’s C-series already shows a balanced approach that serves daily reliability.



What It Means for Future iPhones



The test signals a clear shift in Apple’s modem ambitions. If C1X is a preview, Apple will narrow Qualcomm’s advantage further. More consistent speed, improved efficiency, and tighter platform control point to a full transition to in-house modems across the lineup.



Stetson Doggett’s side-by-side testing on T-Mobile’s 5G and LTE networks, including repeated 5G UC and LTE runs and a weak-signal segment. Quotes and figures reference results observed in that video.





“Apple says its C1X modem is able to achieve similar performance as the iPhone 16 Pro while using 30 percent less power overall.”



“Qualcomm X80 firmly in first place with both the fastest download and upload speeds.”



“The iPhone Air with Apple’s C1X modem had the best peak performance of 1,351 megabits per second.”





Bottom line for you: peak numbers look great in screenshots, but steadier lows, resilient weak-signal behavior, and better battery life define a better phone day. Apple’s C-series pushes that experience forward.