With its iPhone 7 this year Apple decided to make a change and spring for two different chipset vendors: Qualcomm and Intel. The decision created two versions of the new iPhone with different modems – and a new test from Cellular Insights shows they are definitely not equal.

According to Cellular Insights’ report, the Qualcomm and Intel modems come with similar capabilities including three-channel carrier aggregation on the downlink and two-channel carrier aggregation for the uplink. While Qualcomm’s modem could also have included compatibility with 256 QAM and 4×4 MIMO, Apple decided not to include these capabilities. The decision was presumably intended to level the playing field for the Intel modem, which does not offer support for either of those technologies.

But it seems the hobbled Qualcomm modem still performs better than its Intel fellow.

Cellular Insights – which conducted an independent study – used a Rhode &Shcwarz (R&S) TS7124 RF Shielded Box, two R&S CMW500, one R&S CMWC controller, and four Vivaldi antennas to simulate an LTE environment and test performance at varying signal strengths. Cellular Insights said the test covered three LTE bands, including Band 12, Band 4, and Band 7.

What they found was that while the Intel and Qualcomm modems both delivered strong performances when the LTE signal was strong (-85dBm), the Intel modem’s performance dropped off sharply as the signal strength decreased. In Band 12 testing at -105dBm, the performance gap between the Qualcomm modem and the Intel modem hit 20 percent, and leapt to 75 percent when the signal strength was lowered to -108dBm. Performance for the two modems finally came back in line around -121dBm, the report said.

Overall, Cellular Insights found the average performance difference to be around 30 percent, in Qualcomm’s favor.

So why does this matter?

As mentioned above, there are two distinct versions of the iPhone 7 and not all U.S. carriers are getting the same one.

T-Mobile – which, as an aside, could have benefited from the 4×4 MIMO capabilities denied in the iPhone 7 – and AT&T are being supplied with iPhones that use the Intel modem, while Verizon, Sprint, and customers who buy an unlocked device from Apple are getting the Qualcomm version.

And as in the case of poor Wi-Fi connectivity, carriers take the blame when performance fails to meet expectations on mobile devices.

“Most of the time mobile operators get blamed for dropped calls or session timeouts, but it’s often forgotten that the phone OEMs implementation of baseband, RF Front-End (RFFE), and the antenna design could play its role,” the report said.

So remember, if your iPhone 7’s performance is sucky in rural areas or spots with a weak signal, don’t forget to blame Apple, too.