[thewayfarer]

> Under iOS 11.2.0 the effect is even more pronounced.

No, the effect is exactly the same as you can see from the charts since they peak at the same benchmark scores. It is the distribution of those effects that is different, with the performance being negatively affected for more phones. But keep in mind that under iOS 11.2.0, most iPhone 6S's that are tested are probably about 2 years old. Under iOS 10.x, most iPhone 6S's probably about 1 year old. I'd like to know the distribution of the times that these Geekbench benchmarks were run. If scores for one phone model in one month are one average score under iOS (x) but is substantially lower the next month under iOS (x+1), then I would consider that to be a significant act of "planned obsolescence".

But really Apple should probably be more transparent about this. And the bottom line for users is that if you notice any kind of significant performance degradation, whether it is fast battery drainage or sluggish performance, you should consider taking the phone in.