I have exactly the same issue with 3900X and Asus Tuf Gaming X570-Plus. A few days ago about 3 cores were stuck at 500MHz and one was at 1500MHz while the rest were fine. I reseated the CPU and heatsink thinking it was some kind of throttling and it was fixed for a few days. Today nearly all the cores did it, tanking performance in everyday tasks. Restarting fixed it, but I'm really curious what the problem could be. Someone early mentioned the VDDCR SOC voltage shouldn't be as high as 1.362V. Mine is the same and I haven't touched it - that's what the motherboard has set it at according to Ryzen Master.
Edit: I've just checked in the BIOS and the SOC voltage is set to 1.1V, so idk why it's showing so high in Ryzen Master
My 3600x has the same issue. But it‘s not always at 0.5ghz. Sometimes it gets stuck somewhere between 0.5 and 2.5ghz. I tried all the mentioned solutions except the fast boot. Let‘s see if this is going to help.
Since I went amd I had so many issues that changing the powerplan for a second seems like an acceptable solution...
mine also gave this problem in all cores, I use a ryzen 5 2600, and it gets stuck at 0.54ghz, I already tried to solve it with the motherboard manufacturer and it didn't, the bios is up to date, now I opened a support ticket in amd for a solution. Mine only goes out of 0.54ghz if I turn off and on the pc or suspend and return.
Still unsolved, I'm starting to think it's a manufacturing defect of the processor because several motherboards have the same problem.
This can not be a coincidence. My 3900X has the exact same problem, with different brands of motherboard and memory.
At times, some cores get stuck at a very low clock speed.
Just like OP, Cores #0, #1, and #2, are stuck at 559.0 MHz.
This results in terrible responsiveness and performance of my PC! Even opening a folder, browser, or other app takes way too long. Going to fullscreen and back on YouTube takes seconds.
I didn't change anything, this problem suddenly appeared recently. Power plan is set to high performance of course.
Rebooting sometimes seems to fix it, but I'm desperate for a solution. This behaviour is unacceptable.
AMD Ryzen 9 3900X - Scythe Fuma
Gigabyte X570 Aorus Elite
64GB Crucial 3000C16
Palit GTX1070 Super JetStream
Corsair MP510 960GB
Samsung 850 EVO 1TB
OCZ TR150 960GB
Corsair 760T + HX850i
Win 10 Pro
I have had this with up to 9 Cores Affected on my 3900x and the Asus x570-E.
My Solution was to not use a AMD Power Plan I hope it stays fixed.
I was running the memories at 2933mhz which is according to the amd website for ryzen 5 2600 processors and it gave this problem, now I left it at 2666mhz and so far the problem has not appeared and I do not use xmp, I believe that or amd it has the wrong data for the maximum memory or the motherboard.
What frequency of memory do you use?
I encounter this problem with my 3950x and MSI x570 Godlike from November to April with the old bios AGESA 188.8.131.52, old AMD chipset 1.11 and AMD Ryzen Master never installed.
Sometimes at boot I stayed locked to 500Mhz
With the latest bios with AGESA 184.108.40.206, never appended again.
I use now AMD chipset 2.04, AMD High perf power plan and have AMD Ryzen master installed but not used.