Samsung switched to its own Exynos line for the flagship devices with a small number of mid-rangers powered by its own chipsets. However, we can expect this number to grow by next year where the Galaxy line will totally be dependent on Snapdragon. The two chipsets, Exynos 7650 and Exynos 7880 are roughly from the Snapdragon 620 range.
These have a big.LITTLE configuration of Cortex A72 and Cortex A53 and Mali T860 graphics processor. Both these will be built on 28nm range. The difference is in the clock speed where the Exynos 7880 chip takes advantage with an extra core for the GPU and faster RAM access.
Samsung’s Cortex A72 chip is based on ARMv8A and is the successor of the A57 which is used in the current designs. This chip is build to improve the performance and power efficiency of its devices.