With Zen2 you want liquid cooling, believe me. I've got a 3700X and a Black Ridge with Noctua A9-14 in my Dan A4-SFX and it was driving me mad in idle. AMD's frequency scaling is so aggressive that you get temperature spikes and even with a late but aggressive fan curve it leads to constant ramping up and down of the fan. For now I am using a fixed frequency (downclocking still works luckily) to control it. But as soon as the LT240 arrives I'll move back to my NCase.
Thanks for all of the tips guys, I honestly appreciate it. But believe me, I spend hours on this topic. Limiting by PPT, PPT plus undervolting (yielding clock stretching) and it just did not bring the result I wanted. In the end, limiting the voltage and frequency ("manual OC") and living with the performance loss is my temporary fix.
Interesting. From my experience the small NH-L9a (with good airflow) is completely capable to cool the 3700X without any loss of performance and also with silence. I have a thing with noise and is always my first priority.
Also great tips here for fine tuning, just to add, if it's not mentioned already, the importance of using the latest bios and the latest chipset drivers with these Ryzens.
To give an example i have my B450-I from mid 2018, first with 2600 and then with 3700X, i have used every bios that came out from the first release. All the bios for the Ryzen 3000 before the latest one are driving (default settings) the 3700X out of AMD specs (around 15W more power)!.
As an old user of Argus, can confirm that is a great software, but i think for new users and not complicated fan setups, the provided utilities or bios are also fine.