89 is a problem. My CPU is overclocked and never gets above 60. A couple of things to think about.
- Liquid cooling. Surprisingly I got the best result by having radiator fan blowing into the case. This may seem odd to recommend blowing hot air into the case. But this means the radiator is getting cool air from outside the case rather than heated air from inside the case to cool the CPU. You just need to have an adjacent fan blowing out of the case to vent this hot air. I have a single fan radiator blowing in from the rear of the case and another fan immediately above this blow up out of the case. Guess this will not be possible with your 3 fan setup as that is mosty likely mounted at the top. Your RTX3080 is probably generating heaps of heat which you then use to cool your CPU, reducing the effectiveness of your water cooling.
- Case airflow. I usually replace all the default case fans with Noctua fans. Noctua are not pretty but have very high airflow for very low noise for a resonable cost. This allows them to run at max all the time and is not an expensive option.
- Case pressure - Have the same airflow coming is as going out.ie 2 fans in, 2 fans out.
- Lastly give all your air inflow filters (if your PC has them) a vacuum at least every 6 months. They clog up pretty quick, reducing airflow.
While the points above help general cooling, they are most likely not your problem. So it may be that you CPU cooler plate that connects your water cooling to the CPU is not seated correctly, preventing the cooling system from working properly. Might be time to take it off give it a clean, apply some new CPU paste and refit it.
But even this sort of problem is unusual (but not unheard of) as most CPU mounts generally prevent this sort of problem, so one last thing to check is make sure your CPU water cooling motor is working. Mine has a separate power connection, which you have to be carefull not to dislodge.