Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Probably because the 5 had a SIM in it and the others did not. That's my theory.

The SIM status does very little in altering boot times.

nope, this question was asked on youtube, they stated no sim was inserted, after the lock-screen it took an extra second for the no sim card msj to pop up, but it was removed from video.

This is iClarified, they know what they are doing. :)

All three had fresh iOS7 installed.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.