Apple's 2018 iPhone models -- particularly the XS line -- offered the first significant boost to 4G data speeds in several years, according to research firm OpenSignal.
The XS and XS Max are nearly 26 percent faster than all iPhones released between 2015 and 2017, even the iPhone X, OpenSignal found. To gauge performance, the company tested iPhones across the U.S. on multiple carriers between Oct. 26 and Jan. 24.
The Max in particular put Apple's best foot forward with speeds up to 21.7 megabits per second. The standard XS ranked second at 20.5mbps, but the XR was actually slower than the X at 17.6mbps versus 18.5, respectively. Because it uses 2x2 MIMO instead of 4x4, the XR is incapable of the same speeds as the XS.
Bandwidth is said to have stayed largely stagnant between the iPhone 6s and X. This may have diminished people's interest in upgrading to new iPhones, OpenSignal speculates.
Although the first 5G phones and networks are rolling out, Apple isn't expected to adopt the technology until 2020. What coverage exists is limited, and Apple's preferred modem maker, Intel, is unlikely to have a 5G chip ready until next year.
Apple has often been criticized for being slow to adopt new cellular standards. The original 2007 iPhone was 2G at a time 3G was making waves, and the company didn't adopt 4G until 2012's iPhone 5.