Could it be faster

so i have a 4s.. seemed slow and sluggish (talking app speed and flicking between screens)..turned it off, took the sim out, put the sim in, tuned it back on.. did the hokey pokey lol.. and now it sings and zips like ipad - which it did not do before.. could it be faster cuz what i did?

 

oh boy here goes -

have a 4 with the orginal sim

got a 4s which didnt seem fast. took the sim from 4s put it in 4 to re-actiavte that 4.

decided to keep 4s. took the sim from the 4 (which really is the one from the 4s) and put it back in the 4s.

long story short the sim in the 4s is the one that came with it.. but it was in my 4 for a day..

got all that?
how do i make sure i'm on the 4g plan?