With frequencies reaching 2.8GHz, ARM claims that it can add ~30% higher performance*, and sustain that performance better, given the same thermal constraints. That’s because the Cortex A73 has a 30% better power efficiency* (performance per watt) as well. ARM’s customers should build the A73 using a 10nm semiconductor process which yields a tiny 0.65 square millimeter per core. (* compared to a Cortex A72 in 16nm.)
Sustained performance has been a design goal for the Cortex A73. ARM says that there is now virtually no difference between sustained performance and peak performance. Typically, performance can reach a peak, but when the chip gets hot, it needs to be reduced to sustain the activity without overheating. In the past, a core design such as the Cortex A57 could see a difference of ~20% between the two. A72 reduced that a little but A73 nearly eliminates it.
Cortex 73 based designs will most likely also feature the ARM Mali G71 GPU with which it will share some high-speed memory buffers to increase performance during data exchanges between the two.