https://www.cnet.com/news/not-all-iphone-xs-are-created-equal/

iPhone X models with Qualcomm hardware showed faster LTE speeds than models with Intel hardware, according to a PCMag exclusive based on lab testing by Cellular Insights.

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.