5800X3D Overheating

Most of the users who took their time to record the temperatures noted that it easily climbed to 90°C or higher during stress tests and intense games. Now, let’s discuss how to break down the reasons why this occurs, usual user experiences, and ways to combat this problem with effective solutions.

Why Does the Ryzen 5800X3D Overheat?

Aggressive Stock Voltage and Boost Behavior:

To optimize performance, AMD tuned the 5800X3D in a way that results in high voltage and boost activity. I managed to achieve temperatures from 80°C to 90°C when using the CPU at full load, which is in the thermal design power envelope set by AMD.
Inadequate Cooling Solutions:

The 5800X3D will need very good cooling which is why Inno3D has included the NZXT Kraken G12 water cooling solution. Some users have problems even with the high quality air coolers such as Noctua NH-D15 or Be Quiet! Dark Rock Pro 4, and the CPU can still go rather toasty when the cooler isn’t designed to manage such high thermal loads.

Real Users and Typical Issues
User Experience 1:  He said that their 5800X3D reaches 90°C even when running Cinebench and stays above 90°C during gaming with a Dark Rock 4 air cooler. They attempted to resolder the cooler and use fresh thermal compound (Arctic MX-4) which increased the temperature by just a few degrees.
User Experience 2: Chicken Patty said that they observed a huge increase in temperatures when they replaced a 5600X with a 5800X3D, and their setup included two 360mm water coolers. The temperatures of their CPU were still at 90°C at full load, implying that prior water blocks may not be tuned for the 5800X3D.
User Experience 3: One of the community moderators, tabascosauz, said that the thermals on the 5800X3D are even worse than any other Zen 3 CPU. They pointed out that even water cooling can only slightly cool down the temperatures unless you employ a fresh water block designed for the higher density heat of the 5800X3D.

Real Solutions to Lower 5800X3D Temperatures
Optimize Your Cooling Solution:

For those who are using air cooler, it is advisable to go for better cooler such as Noctua NH-D15 or better still, go for the 240mm or 360mm AIO liquid cooler. If you’re into water-cooling, make sure your loop comes with a water block compatible with the latest AMD CPUs such as the EKWB Velocity2.
User Tip: Taking off the side panel of your case can do this in the short term, for instance, taking out the left side panel of the case will do this. Some gamers, like one who mentioned he got from 90°C to around 84°C while gaming heavily in Arkham Knight, have done so.
Undervolt Using PBO2 Tuner:

Currently, there are many reports of users using the PBO2 Tuner to fine-tune the curve optimizer. What we found to be quite effective is setting an all-core negative offset, say from -20 to -30, because it will minimize power consumption and temperatures while not affecting the system’s performance in any meaningful way.
A user who applied a -30 all-core undervolt with 100W power limit saw temperatures drop by 10-20°C, taking the peak down to 75-80°C while gaming.
Reseat the CPU and Reapply Thermal Paste:

Applying proper pressure to the CPU and using good thermal conductivity paste such as Thermal Grizzly Kryonaut or Arctic MX-5 makes a big difference. Make certain the paste is applied evenly and thinly so that a hotspot does not occur.

Improve Case Airflow:

Replace your case fans with high-quality fans and in the process, ensure that the configuration is as follows; more intake fans equals to positive pressure. The ones with front mesh panels appear to do better in regards to heat dissipation.
User Recommendation: A user who moved to a high airflow case such as the Phanteks P400A observed a 5-7°C reduction in peak temperatures.
Limit Boost Behavior in BIOS:

If the above methods do not give sufficient relief one should try to restrict the boost frequency of the CPU in the BIOS. Lowering the maximum boost clock by 100-200 MHz decreases temperatures while taking relatively little hit in performance.
My Personal Real-life Experience 
From my own testing of the 5800X3D, I noticed the same thing, although temperatures do increase quite a bit during CPU-bound operations. I first went with a mid-tier air cooler but using a 280mm AIO (Arctic Liquid Freezer II) and applying a -25 all-core offset through the PBO2 Tuner provided improvements. My peak temperatures came down from 90°C to around 78°C in Cinebench R23 and heavy gaming. I think this setup is good for cooling and good for ventilation but not too loud.

If you are experiencing high temperatures on your 5800X3D, try and reduce the voltage with the PBO2 Tuner and make sure you have the right cooling. It is therefore advisable to spend money on a long-term high airflow case and a good AIO cooler. If you reach 90°C often, do not run the CPU at the standard settings because this reduces the durability of the components.