That’s a Bingo.
At first I wouldn’t get any errors, had to undervolt the memory until the system wouldn’t POST, then increased the voltage one step again so it would be reasonably doubtful that the memory could be stable under a stress test.
So, verified that ECC is also kicking in with a 5950X, unkown PFEH status, and the platform is giving the corresponding feedback to the operating system (motherboard: ASUS ProArt X570-CREATOR WIFI, UEFI 1201, AGESA 120A):
Glad this topic could be resolved and that I haven’t been spouting non-facts since I previously tested ECC with Ryzen 3000 stating ECC worked on AM4.
Can’t say anything about the current state of ASRock except in my opinion their motherboards have become worse feature-wise (currently ECC on AM5 seems to be messed up on ASRock motherboards, working on ASUS motherboards - I can’t verify this since I don’t have an AM5 system yet).
I also know the frustrations of being jerked around by incompetent Tech Support from billion dollar corporations, I’ve been pissed at Broadcom for over a year: