Sectre and Meltdown shook the tech industry - they allow malicious code to peek at protected data. They do it by exploiting CPU features meant to speed up execution, so the solution is simple but unpleasant - devs have to circumvent those performance-enhancing features. We were prompted by the huge performance hit to the iPhone 6 after the update to see if the newer models are similarly affected. So we found an iPhone 8 Plus at the office that was still running iOS 11.1.2 - before either patch. We ran Geekbench and AnTuTu then installed iOS 11.2.2 and ran them again. iPhone...
Source: https://www.gsmarena.com/spectre_and_meltdown_testing_performance_impact_on_iphone_8_plus-news-29132.php