I've got an error log of the time it happened, but it says "illegal opcode in command stream"? This has happened once or twice.
Also my kernel. title Arch Linux (linux)-ZEN linux /vmlinuz-linux-zen initrd /amd-ucode.img initrd /initramfs-linux-zen.img options root=PARTUUID=4d76ca7f-5b26-4ed6-8564-42d1b64ce727 zswap.enabled=1 rw rd.udev.debug=0 rd.udev.timeout=0 systemd.debug_level=0 rootfstype=ext4 amdgpu.ppfeaturemask=0xffffffff
I've also tried with the non-zen kernel with no more success.