Some early iPhone 7 adopters are getting considerably more than they bargained for. Reports are surfacing of both the regular iPhone 7 and the iPhone 7 Plus producing hissing sounds when they’re subjected to a heavy processor workload, such as a game. They continue to function, thankfully, but it’s a bit disconcerting when most phones are virtually silent. It’s not clear what the cause is — some suspect coil whine or similar electromagnetic effects, but there’s no guarantee that this is the case.
The issue doesn’t appear for everyone. I tested an iPhone 7 using 3DMark “Ice Storm Extreme,” a performance benchmark that puts the processor under serious strain, and heard no hissing at all. That suggests that the noise may stem from a manufacturing issue instead of an inherent design quirk. Not that this will make you feel any better if you’re affected, of course.