then Cortex A9 has 2.5 DMIPS/Mhz, while Cortex A15 has 3.5 DMIPS/Mhz, and some manufacturers are even promising 4.0 DMIPS/Mhz. So, the performance per clock compared to Cortex A9 should be 40%-60% higher, all things being equal. This is a huge improvement in efficiency. ...