PC freezes after minutes, but will be stable when underclocked?

My system (system specs are up to date as well):
Windows 10 22H2 (Build 19045.3693)
Ryzen 9 5950X
Gigabyte X570 Gaming X, BIOS F38f, Sep 21, 2023 (latest as of today)
(All other parts have been replaced)

At first it was a freeze now and then. Then it suddenly became worse, now it freezes within minutes after startup. I have replaced everything except the CPU and motherboard. [EDIT: There are no BSOD, just the screen at the time of freeze]

I then tried AMD Ryzen Master and typed in 3000 for the frequency where it used to say 3400. Now it has been running for two weeks without issues. The included picture show my changes in Ryzen Master.

But I would like to regain the original speed of the system. What would be the clever way of doing that. Some kind of overclocking? And is it possible to deduct the source of the instability to CPU or motherboard?

I just tested with a program I am using. A run that takes 54 seconds with no use of Ryzen master takes 77 seconds with the 3000 setting.

CPU usage around 80% for that time.

Megahertz said:

Did you monitored the temperatures?
Is the liquid heat sink well seated over the CPU and did you apply a thin thermal paste layer between them?

When I originally put the system together there were pre applied thermal paste on the heat sink. When this started I ran prime95 and OCCT temperatures ended up around 80C. I have replaced the cooler since then. Right now with the Ryzen Master setting 3000 running OCCT for 1 hour ended up at 60C.

Megahertz said:

80ºC is the max it should go.
Try to set Ryzen Master setting to 3200

Thank for the help. At 3200 the OCCT stress test reaches 58C and the program I am running uses 70 seconds.

I will leave it on over night.

Megahertz said:

If everything OK, set Ryzen Master setting to 3300

It froze again at 3200. Not immediately, but after some hours.