to understand why android is still lag even though using bad-ass specs like quad core and 1GB RAM, u must first understand how android was born.

the person who started android was an engineer working for Apple.
Google chairman also knew abt the idea of touch screen phones when he was board member in Apple.
so android is a copycat system. and like most copycats, they can capture the most parts but not the soul of the thing they copied.

Apple has much experience in graphics design in both hardware and software.
They use this superior knowledge to design and produce the great iPhone.
Like all their products, Apple designs the product where hardware and software are working together as one in perfect harmony.

whereas android is like frankenstein monster. it is open-sourced and designed to fit almost all hardware configuration. this creates the huge problem of fragmentation and the hardware/software are not working together properly.