There is video on YouTube called “Every iPhone Speed Test Comparison 2016”, about 6 minutes, which compares the performance of all iPhone, from iPhone 2G to iPhone SE.
When Apple launched the iPhone 2G in 2007 on the market, Intro was relatively clunky and in retrospect, quite inefficient. Apple, however, has managed to perfect the iPhone over the years and repeatedly to obstruct new and improved components.
The video below is posted by EverythingApplePro and then shows all iPhones comparison, the first model in 2007 to the lastest: iPhone SE. The different modules in the video in various disciplines compete, so as at startup, the WiFi speed, the Geekbench performance test with the camera.