I think that this might take the cake as the silliest “controversy” surrounding an iPhone launch. However if you are concerned that you’re stuck with one of the unclean Samsung phones, you can use this tool linked by Gizmodo to find out. It’s an app store download,
As it turns out, not all new iPhones are created equal. There’s two different versions of the A9 processor, and while they’re mostly the same, one of the chips seems to be killing battery life.
Source: Go Find Out If Your iPhone Has a Good or a Bad Processor
