iAppleBytes ran iOS 27.2 against iOS 26.7.2 on matched pairs of the iPhone 11 and iPhone 12, the oldest phones that run iOS 27, and found no speed gain. The video has no narration; the side-by-side runs through booting, app launches, scrolling and app switching, then ends each phone on a Geekbench CPU run.
Single-core scores barely moved: 1,585 on both versions for the iPhone 11, and 1,794 on iOS 26.7.2 against 1,783 on 27.2 for the iPhone 12. Multi-core went the other way. The iPhone 11 dropped from 3,540 on iOS 26.7.2 to 3,259 on iOS 27.2, about 8 percent, and the iPhone 12 from 4,449 to 4,275, about 4 percent.
The channel's closing card sees no improvement, including the 30 percent speed gain it says was promised for iOS 27.2, and some lag on both versions. It doubts anyone would notice outside a side-by-side test. Its own caveat applies too: the taps are by hand, so small timing gaps are noise.
One Geekbench run per phone is thin evidence for a slowdown, so I'd call it a draw that rules out a speedup. For an iPhone 11 owner the reason to install 27.2 is Apple's security notes, which list 162 fixed vulnerabilities, not performance.
