The study compared performance on LTE Band 4, which is used by most US phone carriers, and showed that when signals were weak (less than -85 dBm), the Qualcomm modem consistently achieved faster speeds. Both models stopped working completely around the same signal strength (-129 dBm), but Qualcomm was faster throughout the testing.
Your iPhone X may vary, depending on which model you have, since both are sold in the US. This information comes shortly after Apple began using both Qualcomm and Intel modems beginning with the iPhone 7 and Cellular Insights found Qualcomm models performed better by about the same margin then as well. The iPhone 4, 5 and 6 all had Qualcomm modems.to try to ban sales of Intel-based iPhone X models in the US.
Despite these positive results with Qualcomm hardware, Apple's relationship with the tech giant has been volatile lately afteragainst each other over patents. Their future together seems uncertain.
Qualcomm declined to comment and Intel did not immediately comment at the time this story was published.