Here are two youtube videos: https://www.youtube.com/watch?v=GV33Qd_jFCQ https://www.youtube.com/watch?v=svaWxFz65SQ The first one is a comparison between iPhone 6 and iPhone 5s on iOS 8, its clearly the iPhone 6 is faster than iPhone 5 on unlocking speed. however the second video show that the touch id on iPhone 5 is super duper fast (under iOS 7.1.1, according to the video), you can barely see the unlock screen (please don't pay attention on that samsung next to it). Then I borrowed a iPhone 5s from one of my friends and registered my fingerprints. I did some speed test on iOS 7 then repeated the test after upgraded the phone to iOS 8 and I noticed that there is a significant speed drop. It seems that unlocking touch ID on iOS 8 is much slower on an iPhone 5S. However, the unlocking speed of the iPhone 5s on iOS 8 is STILL slightly FASTER than my iPhone 6. I thought it's either a bug of iOS firmware or a hardware problem. But soon I noticed that on my iPhone 6, I have "handoff" on. Then I turned it off and gave it another try then the speed on my iPhone 6 is exactly same with my friend's iPhone 5s. So I got this conclusion: iOS8 slows down the unlocking speed, don't know if this is a bug or an intended security concern here; Having handoff on slows down the speed a little bit further and I guess is because the CPU need more power to deal with datas from another iOS/Mac devices when the screen wakes up and this process slows down the unlocking speed; Touch ID censors on two iPhone generations has no difference on unlocking speed. And sorry for my lousy English here.