For the first time this year, Apple went with two different providers of cellular modems in the iPhone 7 and 7 Plus. Some phones have Qualcomm modems, the company Apple has worked with for years. The others had Intel modems, marking a real breakthrough for Intel, which has been trying to get its chips into flagship smartphones for years.
Unfortunately, testing is showing that there’s a big difference between the two modems. Although both will work just fine when there’s a good LTE signal, it seems that if you’ve got an Intel modem, your data speed in areas with less-than-ideal coverage may be much slower.