Buy 3900X, update bios and chipset drivers.Idle temperatures - 45-60-45-50-45-60(voltages 1.2-1.5-1.4-1.3-1.0).When i set turboboost off - temperature and voltage stable.I'm tired.When turboboost is off processor lose 60 points in single core cpu-z and 500 in multicore bench.
Your Rzyen 3900X is rated as a 105 Watt TDP which means you need a CPU Cooler that has a minimum of 130 Watt TDP or higher.
Generally, AMD recommends AIO CPU Coolers or High Quality TDP Air Coolers.
This Windows Tech site offers the best Liquid and Air CPU Coolers for your the 3900X: https://www.windowscentral.com/best-cpu-coolers-amd-ryzen-9-3900x
The AMD Prism which came bundled with the Ryzen 3900X is adequate for normal computer uses. But under heavy stress or loads it may run hotter than a AIO 240MM CPU Cooler or High Quality High TDP Air CPU Cooler.