A little while ago, the Linux-headed sleuths over at Phoronix came across an obscure bug in Ryzen CPUs that triggered segmentation faults ("segfaults," which cause application crashes) in a compiler-specific workload. The bug was confirmed by AMD's engineers, who described it as a "performance marginality problem" and indicated that owners of affected CPUs could reach out to AMD Customer Care. The engineers also noted that Ryzen Threadripper and Epyc processors are unaffected. Phoronix's Michael Larabel took AMD up on its replacement offer and recently received a revised CPU that's apparently clear of the bug.
Larabel performed his due diligence and got to torturing the revised Ryzen 7 1800X under the same conditions that triggered the compilation segfaults. He's happy to report that he came across no issues whatsoever, whether related to compilation or not. The system used for testing was the same for old and revised processors alike. That also seems to clear any suspicion that the bug could somehow also be related to the motherboard or another component.
In his article, Larabel goes on to note that judging from his observations, Ryzen CPUs manufactured before week 25 (mid-June) of 2017 appear to be the ones affected by the problem. The bug is reasonably difficult to trigger, but users that want to rest easy can reach out to AMD Customer Care and get a replacement part.
Segfault bug seems to be solved or at least quite well hidden in newer models. But be warned the MCE Freeze/Reboot bug(1) is still present also in newer versions. And the CPUs in the stores are quite often very old.