Updated September 16, 2026.
Quick Answer
Is the iPhone 18 Pro’s C2 signal worse than the iPhone 17 Pro’s Qualcomm signal? In a test by creator He Tongxue, the iPhone 18 Pro was slower on strong 5G and took longer to reconnect after a complete signal loss.
But the C2-powered iPhone 18 Pro was faster in an underground garage with weaker reception. Both phones completed an elevator call with similar audio interruptions. The results depend on the situation; this test does not show that the iPhone 18 Pro always has worse signal.
Apple’s iPhone 18 Pro specifications list its new C2 cellular modem. Does Apple’s own modem actually improve everyday reception compared with the iPhone 17 Pro’s Qualcomm modem?
Chinese tech creator He Tongxue (老师好我叫何同学) tested 5G speeds, weak-signal performance, calls and reconnection. The comparison begins at approximately 9:07 in his video.
iPhone 18 Pro C2 vs iPhone 17 Pro: What Did the Test Find?
The results at a glance
- Strong 5G coverage: iPhone 17 Pro had faster downloads and uploads.
- Underground garage: iPhone 18 Pro had faster downloads and uploads.
- Elevator call: Both phones connected; both had intermittent audio.
- After complete signal loss: iPhone 17 Pro reconnected faster.
The distinction matters. A speed test, a call in weak coverage and reconnection after losing service measure different parts of cellular performance.
Is iPhone 18 Pro 5G Slower in an Area With Good Signal?
In an area with strong 5G coverage, He Tongxue averaged 14 speed tests. The iPhone 18 Pro’s download speed was nearly 20 Mbps below the iPhone 17 Pro’s, while its upload speed was about 30 Mbps lower. Latency was 1.4 ms higher.
For this strong-signal iPhone 18 Pro C2 vs Qualcomm speed test, the older iPhone won. That is a notable result, but it does not predict speeds on every carrier or at every location.
Does the C2 Modem Perform Better With Weak Signal?
In an underground garage where reception was weaker, the result flipped. The iPhone 18 Pro delivered faster download and upload speeds than the iPhone 17 Pro, and its latency was 1.2 ms lower.
This suggests the C2 may perform well in some weak-network conditions. It does not prove that C2 is better in every basement, rural area or carrier network.
ZEERA’s take
The most useful finding is the change in ranking: the iPhone 17 Pro won the strong-5G speed test, while the iPhone 18 Pro won the underground-garage data test. Calling either modem the overall winner would hide that difference.
Are Calls Worse on the iPhone 18 Pro?
The reviewer placed calls from an elevator with very poor reception. Both phones connected, but speech was intermittent on both. He reported no major difference between them in this test.
So this video does not show that iPhone 18 Pro calls fail more often than iPhone 17 Pro calls. More tests across carriers would be needed to judge everyday call reliability.
Why Did the iPhone 18 Pro Take Longer to Reconnect?
To test network recovery, He Tongxue put both phones in a signal-blocking box until they disconnected, then removed them and timed reconnection. Across 10 repetitions, the iPhone 18 Pro averaged 5.2 seconds. The iPhone 17 Pro averaged 1.5 seconds.
That 3.7-second gap is the clearest drawback for the C2 in this comparison. Someone leaving a tunnel, elevator or underground parking area could notice slower service recovery. The test does not establish why the gap occurred.
Does Apple’s C2 Claim Contradict These Results?
No. Apple says C2 improves upload performance compared with C1X, its earlier in-house modem. He Tongxue compared C2 with the Qualcomm-equipped iPhone 17 Pro. Those are different comparisons.
Actual 5G speed also varies with the carrier, network load and supported bands. Buyers in the U.S., UK, Germany and France should look for tests on their own networks before assuming these results will repeat locally.
Should You Upgrade From iPhone 17 Pro for Better Signal?
Not based on this test alone. If your iPhone 17 Pro already has reliable coverage, the C2 modem is not yet a clear reason to upgrade. The 18 Pro performed better in one weak-signal data test, but worse in the strong-5G and reconnection tests.
If you are upgrading for the camera, battery or other features, choose accessories for those needs. A charger, car mount or case cannot repair a weak carrier network.
FAQ: iPhone 18 Pro C2 Signal
Is iPhone 18 Pro signal worse than iPhone 17 Pro?
It depends on the test. The 18 Pro was slower on strong 5G and reconnected more slowly, but delivered faster data speeds in an underground garage.
Is the C2 modem slower than Qualcomm?
It was slower than the iPhone 17 Pro in this reviewer’s strong-5G speed test. The same comparison favored C2 in the weak-signal garage.
Does iPhone 18 Pro have worse call quality?
The elevator test found similar results: both calls connected, and both had intermittent audio.
Does iPhone 18 Pro take longer to get signal back?
In the reviewer’s signal-blocking-box test, yes. It averaged 5.2 seconds to reconnect, versus 1.5 seconds for the iPhone 17 Pro.
Can a MagSafe case or car charger improve iPhone signal?
No. These accessories serve protection, mounting or charging needs. They do not increase carrier coverage or modem speed.
Sources: He Tongxue’s iPhone 18 Pro comparison, beginning around 9:07; Apple iPhone 18 Pro technical specifications; Apple’s iPhone 18 Pro announcement. Speed, call and reconnection figures are attributed to the creator’s tests, not to ZEERA testing.
