Hi huntcrash,
where are you reading the CPU frequency? (task manager/Ryzen master?)
That you have water cooling does not mean that heat is not a problem, actually, a water cooling makes it sometimes more difficult to identify issues (i.e. in closed loops it's not immediately noticeable if the pump fails).
Can you add some more information:
- Try to access the bios, from within you should be able to see the frequency and temperature of the CPU
- What kind of water-cooling do you have? is it a custom loop or a closed-loop? Does it have a brand/model?
- When you were playing No Man's Sky what was acting strange? (i.e. slow? unresponsive?)
Try to add as many information as possible (you can find a list of common information here: https://community.amd.com/thread/196209 )