Although (disregarding core 1) the other three cores suggest an uneven thermal spread / cooler tension issue.
It is normal for for core 1 to be higher than others, but the other three (unless under load at the moment of that screen shot) point towards an element of unevenness. Under proper idle conditions, they should be closer to the core 4 reading.
The mobo sensor suggests a decent ambient case temp. Core 2,3 should be more in line with core 4 - But - even if left alone, everything is still within 'safe and comfy' specs.
(Core 1 is invariably hotter, since by default it does 'more work' than the rest'.)
From that screenie, your chip is not in danger at all - however it does tend to indicate that:
A) the thermal paste is not evenly spread - or -
B) The cooler mounts are unevenly tensioned.
Core 2,3,4 should generally be a lot closer temp wise together than they currently are.
I assume this at stock voltage / no overclocking and did you build this rig yourself?
Watercooling is not necessary from those temps at all.