If you have an older iPhone – specifically, something from the iPhone 6 or 6S range – chances are you’ve noticed some slowdown since you first picked it up. Same goes for those with several-year-old iPads.

Well, we spotted a pretty interesting piece over at 9to5Mac today, based on findings from a Reddit thread, that suggests the slowdown could be reversed by picking up a new battery.

There are some interesting technicalities at play here – batteries are expected to weaken with time, of course, and Apple offered free repairs a few years back for iPhone 6S users after a bad batch caused device shutdowns.

What’s less expected, though, is that it seems Apple avoided similar issues for other iPhone 6S users by releasing an iOS update that automatically throttled performance when the battery is low to avoid further issues.

This information isn’t official, and Apple has yet to comment – but several users have reported their devices scoring much lower than expected on Geekbench tests designed to check processing power. In these cases, inserting a new battery provided significant improvements to the speed of the device in both real-world and test scenarios.

Of course, this is based on anecdotal evidence and it’s worth reading the full explanation of the details before you take action. But if true, this means that users with older iPhones and iPads could improve performance and eke a lot more use out of their device by upgrading the battery.

Apple will replace a defective battery for free while it’s under warranty, but even these older devices can usually be upgraded for around $80/£80. You may even be able to find something cheaper by shopping around at third-party repair stores.