IPhone SE 2020 : Peak Performance Capability - What it says...?

Yes, the wording is different on newer devices. They are more able to dynamically manage power usage and balance it with performance needs.

I’ve been trying to discern this myself. Newer desktop cpus can change the speed they operate at. I’m assuming newer iPhone cpus have this feature as well. Meaning your iPhone could use slower speeds if you don’t demand it to preserve battery life. Texting is not a game, does not require the performance so why not slow down the cpu even if the battery is perfect. It would cause less drain and get more battery life and therefor longer battery life. I’m only guessing that Apple has turned this on because my 12 Pro Max is at 83% but has your message. I’m right now trying to figure out if it’s being throttled more than normal for the newer phones. I haven’t. Noticed any performance degradation but I don’t do too much exciting stuff so I don’t know. I seem to recall it at some point saying peak performance and now it says your message. Keep in mind it could have been an iOS change. I also could be confusing that with my 10XS Max. Basically I believe your iPhone is always being throttled depending on the CPU/GPU requirements at the moment, the temperature, and then later because of also battery degradation. I haven’t found the answer but apple uses 80% for warranty replacement. Does a new phone read your prior message I don’t know. I do know I have not noticed any slow downs. If you notice slow downs then that’s a good sign your battery needs changing. Even if it needs changing such as at 79% and you don’t notice any slow downs then I would. Personally wait till I did to change it. I know it’s not the perfect answer but with variable cpu speeds these days why go 100% full throttle when you are texting? Why not save battery longevity and increase operating time on single charge? Should you play a game it should ramp up to whatever that game needs or whatever software you are running. I know it’s not a perfect answer so my best guess is, if your battery is above 80% and you notice no problems then I wouldn’t worry what it says. There is also benchmark software so you use it when it’s brand new and you can test it in the future. Keep in mind, iOS upgrades can normally speed up or slow down an original benchmark. However if your new number after a year or two is significantly slower say 20% lower or it turns off while running then it’s time for a new battery. Sorry I couldn’t have a direct answer as I don’t have a new phone and can’t tell if it changed when I upgraded to iOS 15.5. I can tell you it does everything I throw at it like day one including games 1.5 years later and at 83% battery life. Hope this helps.

Protect & Prolong the life of your iPhone's Battery: Batteries - Maximising Performance - Apple (IN)