The Sony Xperia S became Sony's first dual core handset and was just released. This comes 14 months after the first dual-core handset was released - the LG Optimus 2X. It now turns out that Sony may take as long as early 2013 before they release their first quad-core handset.
This was revealed by Stephen Sneeden, Product manager for Sony, who pointed that that modern smartphones do not require quad-core processors yet and that the performance gain it not worth the power consumption. He went on to say that Sony will get on the quad-core band wagon when the performance meets power efficiency on these devices.
This conclusion does have some base to it. Current Android devices are known for being battery hogs, and the powerful processors along with the demand for LTE will only continue to put pressure on the smartphone's battery. But Sony has also got to realize that the end user would probably be won over by the higher specs and would choose a quad-core competitor without realizing the implications.
source - CNET