Yes... That's Celsius... I replaced the stock AMD Wraith Prism air cooler with a Corsair H115i RGB Platinum AIO. That dropped the temps to about 40-45 degrees idle and 85 degrees from 95 under load. Also, the CPU voltage would never drop below 1.375 V. AMD has never released the 3900X's TJMax but many speculate it is 95 degrees. I feel that 95 degrees is to hot and may shorten the CPU's life and reliability. Hopefully, BIOS updates will fix these issues in the near future.
I then went into the power settings in the control panel and changed the plan to AMD Balanced. I also changed the CPU load to a max of 99%. That dropped the temps further to 40-45 degrees and about 70-75 degrees under load. That does limit the CPU to 3.72 GHz and prevents it from going to boost mode (BTW, my CPU has never attained the max 4.6 GHz, the max I have seen was 4.55 GHz). I noted once the CPU goes into boost mode the temps skyrocket. But once I limited the CPU to 99%, the voltage dropped to 1.1 V.
Using the Power Saver plan and dropping the minimum CPU speed to 5% will drop the idle temp to 38-40 degrees, the CPU speed to 2.8 GHz and voltage to 0.9 V. When putting the CPU under load, it will ramp back up to 3.7 GHz..
I use my PC primarily for encoding videos using Handbrake (I don't play any games, that's why I went with the AMD Ryzen 3900X, it handily beat the Intel i9-9900X in productivity applications). On my old Intel i7-6700K PC the program would hit 100% CPU usage all the time when running Handbrake. The 3900X never peaks more than 80% CPU usage with Handbrake, which means the CPU is never stressed by the app. When restricting the CPU speed to 99% made absolutely no difference in the time to encode a video. What took 120-150 minutes on my old i7-6700K PC now takes about 35-45 minutes, on the same encoding quality (HQ or SHQ mode).
On a side note. Handbrake has the ability to use the GPU to encode videos. I now have a NVidia RTX2070 GPU. When using the GPU to encode videos, the speed is notably quicker, dropping the encode time to 10-25 minutes. I imagine the latest GPUs from NVidia would be even faster, maybe 5-15 minutes with the RTX2080 Super or Titan GPUs. I understand by using Intel's QSV mode in their latest CPUs is supposed to be even faster)
I have run into some compatibility issues with videos encoded with QSV. But all is not perfect with the Ryzen. I have found a couple of minor apps that will not run on the AMD CPUs but run fine on Intel systems (confirmed by the app developers).