Apple A9 vs Snapdragon 805

[Smartphone2016]

Hey guys, I'm new here and I have a question about CPU'S that I hope you can answer. I've read online that the Apple A8 was faster than the 805 even though the A8 has a lower clock speed. I know one of the reasons is that the A8 is made for iOS but I am generally wondering how the A8 is faster in single core speed. If anyone has an answer, feel free to reply. Thanks.