It appears the A5X processor was designed specifically for the iPad according to reports. The A5 dual core was chosen because it is good with battery consumption and had enough power to do the job. Many manufacturers have not gone to quad core processors because there are very few programs that can take advantage of four cores. However, more cores for the graphics is a good way to improve performance. Because of the lack of any need for quad core graphics on the iPhone, it is unlikely that it will havethe A5X, and maybe not even get a different processor in the next model.