Apple still has time to fix it.
Apple continues work on iOS 12, correcting the mistakes and improving the optimization with each new beta version. However, the actual fifth test build of iOS 12 are unable to please the user. Speed iOS 12 beta 5 has slightly decreased on older iPhone and iPad models.
Testing iOS 12 beta 5 showed that the performance of the firmware on older devices lower than iOS 4 beta 12. The difference in speed between the firmwares is small, but, nevertheless, it is. Most of all it is noticeable on the iPhone 5s — the old Apple device with iOS 12.
It is important to note that as with the previous beta version of iOS 12, the fifth Assembly is much faster iOS 11. But further improvements in terms of performance in the firmware does not occur. It is expected that Apple is satisfied with the speed of iOS 12. And this position is quite easily explained. Newer iPhone and iPad models running iOS 12 work very quickly.
On the other hand, Apple still has plenty of time to speed up iOS 12. The final version of iOS 12 will be released in the second half of September. As in previous years, the latest beta firmware version will show the real performance of the system.