Apple always keep updating the latest firmware for those old devices, they endeavor to enhance the operation speed of the older device in every update, the company rolled out iOS 9.3.3 beta 1 earlier this week, which also supports iPhone 5. iPhone 5 released on September 2012, that is indeed a great work to ensure the iPhone 5 running on iOS 9.3.3 smoothly. So some people made some basic tests to compare the speed of iPhone 5 running on iOS 9.3.3 and iOS 9.3.2.
The below is a comparison video by iAppleBytes, they made the test through a whole bunch of everyday usage tests alongside a second unit running iOS 9.3.2. The difference is noticeable right at the start of the comparison video, with iOS 9.3.3 booting up ever so slightly faster.
We can see some things, like Messages and Twitter, are faster under the newer software, other things seem a little slower — like loading times for the App Store and webpages in Safari.