I recently finished a new build with a Ryzen 7 9800X3D, RTX 5070 Ti, and Lian Li HydroShift II LCD-S 360mm AIO with UNI-SL Wireless fans. The CPU idles around 50–55°C, which seems warmer than expected for a 360mm cooler, but gaming and multitasking temperatures stay below about 75°C. HWiNFO64 shows that none of the CPU temperature or hotspot readings have reached 80°C, and the system is otherwise working normally. I have not run Cinebench or another dedicated stress test yet. Are these temperatures typical for Ryzen X3D processors, or should I check the cooler mounting, thermal paste, pump and fan curves, airflow, or background processes?
4 Answers
Before changing anything, check airflow, fan operation, dust buildup, and whether the case has enough clearance from the wall. Also look for background applications causing frequent boost activity. A 9800X3D sitting in the 40s or 50s at idle and reaching the 70s under gaming or compilation workloads is commonly within normal behavior.
A loose mounting screw can make a noticeable difference. One owner with similar temperatures dropped from about 52°C idle and 65–70°C in games to roughly 42–43°C idle and 50–55°C while gaming after remounting the cooler. It is worth checking that the block is evenly tightened, though your current load temperatures already look healthy.
Check how the AIO pump is configured in the BIOS or its control software. Setting a minimum pump speed—around 50% or even a constant speed—can lower idle temperatures if the pump is currently slowing down too much. Keep the radiator fans quiet at idle if you want, but avoid letting the pump stop or drop excessively low.
Those temperatures are generally normal. Ryzen processors can sit warmer at idle because they boost briefly in response to background activity, and idle temperature is less important than sustained load temperature. Staying under roughly 75°C while gaming is a very good result, so there is no obvious reason for concern.
I’ll check the mounting pressure and pump settings, then run a proper stress test to compare sustained temperatures.