Why all the 3g phones give different speeds? so plz tell me a better 3g speed phone mor than 500mbps,1mbps?

I just want to know the answear?Why all the 3g phones give different speeds? so plz tell me a better 3g speed phone mor than 500mbps,1mbps?
It depends on the chipset used by the manufacturer, the better the chipset the higher cost the phone. It also depends on your network operators speed capability and how many users logged onto the network at one time as to what speed you can achieve.