Originally Posted By: Faolan
It makes me wonder if their attempts to address that issue in software/firmware first helped contribute to this new report.

Some great research of existing data by the folks behind Geekbench is helping to show the two situations do indeed appear related:
https://www.geekbench.com/blog/2017/12/iphone-performance-and-battery-age/

(Amused that in the great tradition of these boards, we're discussing an iPhone 6s issue in an iPhone 6 thread, that was bumped iniitally for Doug to see a possible upgrade to his amazing smartwatch due to the years old parallel discussion of the Apple Watch announcement smile )

Will be curious to see what future iOS updates do in regards to this issue. Not as directly interested though as the 6s I had was sold prior to the announcement of the 8/X, though I do have one family member to look after with a 6s. No signs of the bad battery issue, and this performance gating to preserve the battery shouldn't impact them much.