I have Ryzen 7 1800X, ASUS Prime X370-PRO, running Fedora 26 and 27.
The damn thing has not worked properly since I bought it.
My first CPU was RMA'd, and the replacement does not appear to suffer from the SEGV fault.
However, both the original and the replacement CPU both crash regularly:
* occasionally with streams of "watchdog: BUG: soft lockup" events being logged,
* but mostly the system just stops and I can find no logging that tells me why.
At bugzilla.kernel.org I find bug 196683, where a "workaround" is suggested:
1) kernel configured: CONFIG_RCU_NOCB_CPU=y
2) kernel command-line: rcu-nocbs=0-15
But with kernel 4.14.18-300.fc27 I find the machine has stopped over night (when it is idle), every two or three days.
I have added kernel command-line "processor.max_cstate=5", which may help with the crashes, but (I assume) not with the electricity bill :-(
Does anybody understand what the real fault is ? A "workaround" is all very well, but not entirely satisfactory. It's not as if this is a new device any more.