Apple A6X (APL5598) 

The rest of the A6X's extra size is taken up mostly by a larger 128-bit memory controller (compared to the 64-bit controller in the A6), which should keep those graphics cores fed with information and improve on the A6's already-impressive memory bandwidth scores in our benchmark suite.

Each of the four SGX554 cores features double the arithmetic logic units (ALUs) as the SGX543MP4's cores, meaning that each individual graphics core should be about twice as fast as an individual graphics core in the previous iPad.