Hi,
Same problem for me on my 3900X. The difference is that error happens on CPU:0.
I've got the error sometimes with a frequency of 15 or 20 minutes. If I do nothing, I have a kernel panic and a reboot. Generally, I reboot before crash to make MCE errors disappear.
I run with this config and, for games, with Linux 5.11.12 (locally compiled) :
$ screenfetch
`..---+/---..`
`---.`` `` `.---.` OS: Neon 20.04 focal
.--.` `` `-:-. Kernel: x86_64 Linux 5.10.28-amd64
`:/: `.----//----.` :/- Uptime: 5h 42m
.:. `---` `--.` .:` Packages: 2235
.:` `--` .:- `:. Shell: bash 5.0.17
`/ `:. `.-::-.` -:` `/` Resolution: 3640x1920
/. /. `:++++++++:` .: .: DE: KDE 5.80.0 / Plasma 5.21.4
`/ .: `+++++++++++/ /` `+` WM: KWin
/+` -- .++++++++++++` :. .+: GTK Theme: Breeze [GTK2/3]
`/ .: `+++++++++++/ /` `+` Icon Theme: breeze
/` /. `:++++++++:` .: .: Disk: 2,1T / 4,5T (48%)
./ `:. `.:::-.` -:` `/` CPU: AMD Ryzen 9 3900X 12-Core @ 24x 3,8GHz
.:` `--` .:- `:. GPU: AMD Radeon RX 5700 XT (NAVI10, DRM 3.40.0, 5.10.28-amd64, LLVM 11.0.1)
.:. `---` `--.` .:` RAM: 13489MiB / 32095MiB
`:/: `.----//----.` :/-
.-:.` `` `-:-.
`---.`` `` `.---.`
`..---+/---..`