There is one more bug in Ryzen CPU, which still exists after BIOS update to version AGESA 184.108.40.206a. It affects Ryzen users of TN-Grid projects who want to use FMA app version. Apps without FMA instructions (AVX, SSE2) are fine. What is interesting, crash signature is always the same:
Privileged Instruction (0xc0000096) at address 0x00000000004f5458
I am author of this app, so I did some analysis and found that for some reason Ryzen loads instruction from incorrect address (in the middle of valid one). This invalid instruction is STI which is a privileged one, what causes crash.
More details are on TN-Grid project forum: http://gene.disi.unitn.it/test/forum_thread.php?id=167