Geekbench Results Visualize Possible Link Between iPhone Slowdowns and Degraded Batteries (geekbench.com)
Earlier this month a post on social media which suggested that Apple might be deliberately downgrading performance on iPhone models with degraded battery was widely circulated. Benchmark Primate Labs' Geekbench has looked into the matter and is corroborating the claims. From a report: Primate Labs founder John Poole has plotted the kernel density of Geekbench 4 scores for iPhone 6s models running iOS 10.2, iOS 10.2.1, and iOS 11.2, visualizing an apparent link between lower performance and degraded battery health. The charts show that on iOS 10.2, the vast majority of iPhone 6s devices benchmarked similarly in performance. However, Poole explains that the distribution of iPhone 6s scores for iOS 10.2.1 appears multimodal, with one large peak around the average and several smaller peaks around lower scores. In other words, after iOS 10.2.1 was released last January, the performance of a percentage of iPhone 6s devices began to suffer.
Let's look at this from a usability perspective. If you make a device with a non-replaceable battery and you want the device to have good battery life for as long as possible, what would you do? I would decrease the processor speed/energy demands as the battery gets older and the capacity diminishes, thus artificially making the battery appear to retain its original charge time as long as possible.