I understand that this SoC only supports lpddr3 and emmc 5.1 and not the newer faster much more power efficient lpddr4x and ufs 2.1 probably for cost reasons (the Snapdragon 630 does support those, but is newer and probably much more expensive as well as the components)

But does the screen have Panel Self Refresh technology? The screen could still be power efficient, if the other components can't.