We've heard complaints about this since the launch of the iPhone 7. Users claimed that the Intel modem found in the AT&T and T-Mobile models didn't perform as well as the Qualcomm one in Verizon and Sprint devices.
Cellular Insights compared the performance of both the Intel XMM7360 modem and the Qualcomm MDM9645M using a Rohde & Schwarz (R&S) CMWflexx setup containing two R&S CMW500 and one R&S CMWC controller, as well as the R&S TS7124 RF Shielded Box with four Vivaldi antennas.
At -96dBm the Intel variant needed to have Transport Block Size adjusted as BLER well exceeded the 2% threshold. At -105dBm the gap widened to 20%, and at -108dBm to a whopping 75%. As a result of such a huge performance delta between the Intel and Qualcomm powered devices, we purchased another A1784 (AT&T) iPhone 7 Plus, in order to eliminate any possibility of a faulty device. The end result was virtually identical. We are hoping that this sudden dip in performance at a specific RSRP value will be further investigated by the engineering and hopefully resolved. At -121dBm, the Intel variant performed more in line with its Qualcomm counterpart. Overall, the average performance delta between the two is in the 30% range in favor of the Qualcomm variant.
The site tested performance on bands 12, 4, and 7. The same performance difference was noted on each band. In fact, the Intel modem performed even worse than the modem on the iPhone 6s at most signal strengths.
Have you noticed a difference in your LTE performance since getting the iPhone 7? Let us know in the comments!