It has taken me this long to write this guide because I don't get free stuff sent to me so I had to wait until I was able to get hands on experience with this CPU and its two chiplet design.
So I am sorry if you have been having a bad experience trying to make sense of what "influencers" who do get free stuff have confused you with regard to the ultimately pretty simple task of configuring your system for optimal stable performance.
I hope this now makes up for my tardiness.
Today someone approached me on Discord who was confused about configuring his 3900X system and asked me to help. He knows me and was thus willing to allow me to use Teamviewer to access his system, and was willing to spend the time with me to allow me to do the job right (which took over six hours of configuring and testing).
First of all any and all settings in Ryzen Master under the heading "Default", "Precision Boost Overdrive" and "Auto Overclocking" are useless.
The other thing is that although the cooler that comes with the 3900X is actually not bad, it is however useless if you want to optimise your system because the Ryzen 3900X is very sensitive to temps and even a difference of 2° C makes a difference with regard to how high you can go with your clockspeeds
This is not to say that Ryzen Master is useless and it is a useful tool.
Forget about trying to set up your system in the BIOS because that is a total mess and you are best off just leaving most of it set to auto (unless of course Auto does something silly such as setting the BCLK above 100).
So here we go, and when I am done you will say, "This is obvious, how come nobody else has told me about this".
The very first thing to do is in Ryzen Master go to "Profile 2" (I will explain why Profile 2 further down) and set the Control Mode to "Manual".
After doing this, go to "Voltage Control" and set "Peak Core(s) Voltage to 1.3 Volts.
Next go to "Memory Control" click on "Included" and make sure that he slider is set to half of the rated value of you RAM (that is, if you have 3200 RAM you set the slider to 1600).
The next part is now really easy. Click on all the cores in CCD0 and CCD1 and set them to a speed and test that.
I started off with 3900 and worked my way up, because this was my first ever experience with a dual chiplet Ryzen CPU.
When you have set the value then go into Cinebench R20 and under "File" then "Preferences" set the "Minimum Test Duration" to 300 seconds. This will run through the Cinebench test multiple times.
Now gradually increase the clockspeed of the cores and test, until it becomes unstable and Cinebench won't complete the test run.
Congratulations, you have found the sweet-spot for your CPU and what is more, that clockspeed will give you a higher single core score than setting Ryzen master even to "Auto Overclock".
With regard to the system I was configuring today the sweet spot was at 4250 MHz for all the cores. I did manage to do a couple of single runs of Cinebench at 4300 MHz on all cores, but it was not stable over the 300 second run, even when I punted in higher voltage and the Cinebench score at 4300 was only about 100 more than the score at 4250.
So that was easy right?
But wait, there's more.
Remember when I said that you were to configure "Profile 2" and I would explain why? What follows will be the reason.
For gaming performance clockspeed is important. Most games don't use more than four cores and very few games use more than six cores.
So now that you have configured "Profile 2" you take those values and apply them to "Profile 1" and then the only thing that you change is under "Additional Control" you set "Simultaneous Multithreading" to "Off".
After you reboot you will have a straight 12 Core/12 Thread system.
The first thing that you will notice when you run Cinebench is that your temps will be a lot lower - and this is what we will exploit (in the system I was working with this was a difference of 10° - 13° C).
Now you can find the sweetspot for this configuration - in the case of the system I was working with today it was stable at an all-core speed of 4.35 GHz.
So now you have the best of both worlds, a 12 Core/12 Thread "Profile 1" for gaming and a 12 Core/24 Thread "Profile 2" for production work where you need the extra threads.
You can get even more gaming performance out of your system than this if you follow another guide I wrote which you can find here:
If anything is unclear then please feel free to ask.
I will then use your feedback to update this post.