Taming the 3950X
Using custom water and PB2 I saw temperatures upwards of 79c. When manually overclocked, things obviously got worse in some tests reaching temperatures of 85c in some cases. While this sounds kind of bad, its nothing compared to Intel’s Core i9 10980XE, which can actually hit 110c on some cores if you clock it to high.
Running all core overclocks on these things produces much higher than normal temperatures. It’s not usually worth doing and while temps do play a part in our limitations here, simply not seeing high temperatures doesn’t mean that your cooling is adequate. Keep in mind that AMD seems to have a target temperature of 68c, and low PPT, TDC and EDC values that seem to be designed to keep the CPU clocks down low enough to keep temperatures in that range. When you raise these values, clocks increase somewhat, but temps go up considerably as a result.
From what I’ve been seeing on various forums, air cooling often nets less than stellar results and thus, sub-4.0GHz all core clocks in multi-threaded workloads and benchmarks. Given what I’ve seen these CPU’s hit using automatic overclocking in Ryzen Master or manual overclocking, I can see why. Even under the same exact conditions, albeit with colder ambient temps the 3950X clocked lower under PB2 than the 3900X did. This is the reason why it suffers in some benchmarks despite having a higher single-core boost rating than the 3900X.
We don’t have a high-end air cooler on hand or I’d have tested it. But based on the data we’ve seen and shared here, there is virtually no chance that you aren’t leaving at least some performance on the table by opting for air cooling instead of a high-end 360mm AIO at the very least. Custom water cooling will produce better results. Given the cost of building a good water cooling setup, I can see why some people would be hesitant to go that route despite spending $750 on a CPU. A good setup is going to be at least $400-$500 and it does require more maintenance to deal with and more skill to put it together. First-timers will waste more money than they need to by not accounting for every fitting, length of tubing, or flat cutting tubing wrong or whatever. They might need a different case or have to buy some tools to get the job done.
I’d say that at a minimum, you want a really good AIO for the 3950X. Custom water cooling will yield better results, albeit at a much higher cost.