According to AMD, the Maximum Operating Temperature for your Ryzen CPU is 95 Degrees Centigrade. So as long as it stays below 90 you should be okay. I did read in one of the Forums in a comment that stated that at 95c is the temperature in which the computer will be shut down by the Ryzen CPU. But that the Ryzen CPU starts to throttle at 80c and above temperatures.
You can try and configure the CPU Fan in BIOS to be more aggressive in cooling. Also in BIOS there might be some settings (Precision Boost is one) that may make your CPU run cooler.
I would make sure you have the latest Motherboard BIOS and CHIPSET installed. That can make your Ryzen CPU run better and cooler. I have read that a faster RAM Memory also will make your cpu run cooler.
If none of the above works, then you may need to install a more powerful CPU Cooler like a liquid cooled CPU Cooler or more powerful air CPU Cooler.
Rendering puts a huge amount of load on the CPU.
This website compares the three AMD Wraith CPU coolers that comes as a stock cooler on a Ryzen 5 2600 CPU. AMD Stock Coolers Tested: Wraith Prism vs. Wraith Spire vs. Wraith Stealth - TechSpot
The AMD Wraith Stealth stock cooler may work fine under normal computer use, but since your are Rendering which normally is very CPU intensive you may want to replace the stock CPU Cooler with a more powerful air or liquid CPU Cooler.
NOTE: if your idle CPU Temperatures are above 50c then you may want to check your CPU Cooler that it is installed correctly or working correctly. This is a thread at Tom's Hardware website about normal Ryzen 5 2600 idle temperatures with stock cooler: Are these temps normal for ryzen 5 2600? - [Solved] - CPUsSuperGhost said:
Hi everyone, i've recently build my PC and im a bit worried about the temps i'm getting im not sure whether these temps are normal are not for my ryzen 5 2600,I average about 45-50 c idle and when gaming my temp tends to be around 64-66 c (tested in pubg,realm royale) i tested cinebench and my temp was 74 c this is on stock cpu speeds using the stock cooler.Also is fairly hot where I live with temperatures reaching 33 at daytime so that would make my ambient temperature a bit high i would think so would that taken into consideration are these temps normal or did i do something wrong while installing?
Those are normal temperatures with the AMD stock cooler.
You never said at which voltages it's operating when hitting high temps. Left to it's own devices, most BIOS put too high voltage at default. All 3 of my Ryzen chips (1600x, 1700x and 2700x) I was able to set voltage not to exceed 1.4v at full OC frequency. There is also -20c offset in first series of Ryzen and -10c offset in Ryzen2 so BIOS and SW may not be adjusted for it. HWInfo hwinfo.com/download.php is most accurate program for Ryzen and shows both temps.
ipc, the offset temperatures posted above are wrong! The only thing that is important concerning CPU temperature is what Ryzen Master (RM) reports. All else should be ignored! Change your cooler if you like, but post a screenshot of Ryzen Master (RM) to see what is possibly going on. Enjoy, John.