Apple has built a reputation for its meticulous quality control demands and tight supply chain management. But it looks like modem problems are haunting the company these days.
Previously, Apple hired the services of TSMC and Samsung to manufacture SoCs for their iPhones but stuck with Qualcomm modems for its hardware. With the release of the iPhone 7 and iPhone 7 Plus, Apple used Qualcomm's silicon modem (MDM9645M) for its factory-unlocked handsets sold through Verizon and Sprint; while adopting Intel modems for its T-Mobile and AT&T devices.
An analysis by Cellular Insights showed that the Intel- and Qualcomm-powered iPhone 7 performed equally well under strong signal conditions. However, the device running on Intel XMM7360 modem showed a significant drop when the signal weakened.
The test conducted by Cellular Insights used a test rig, which allows them to alter the cell signals at will. They tested three LTE frequency bands namely Band four (20MHz), seven (20MHz), and twelve (10MHz) in a 4x4 MIMO configuration. The Band 4 being the most common frequency band for LTE deployments in North America.
Results showed that iPhone 7 with Intel chipsets performed worse in places with weak cellular signals. At worst, the iPhone powered by Intel modems was 40Mbps slower as compared to the Qualcomm-powered device. Although when cellular signal exceedingly bad, both variants have a couple of megabits difference.
It is worth noting that the iPhone 7 with Intel and Qualcomm modems were also compared against the iPhone 6S, Nexus 5X, LG G5, and Galaxy S7 Edge.
Overall, both iPhone 7 variants were beaten by Samsung's Galaxy S7 Edge in all the tests. The iPhone powered by Intel XMM7360 was the worst performer of the bunch although the iPhone 6S did not fare quite well either.
It would also be interesting to have a comparison of how the battery life fares between the Qualcomm and Intel iPhone handsets. It is also possible that the performance on Intel modem devices could be fixed and improved via a software update, which Apple recently released but unfortunately only works on Verizon-locked units.
Customers under contracts with Sprint and Verizon and those with SIM-unlocked units have Qualcomm chipsets running their iPhone 7 or 7 Plus. Devices bought from other networks have the Intel variants. To find out which specific modem users have on their devices, simply look at the model number at the back of the iPhone. The ones with A1778 and A1784 are running on Intel modems while those with A1661 and A1660 are powered by Qualcomm chips.
For users who care too much about LTE performances or those who live in places with trivial LTE cell coverage, buying the unlocked version of the iPhone 7 or 7 Plus is the best way because the Intel modem variants are not performing as well as they should be.