It  is  no  longer  "optional"  to apply firmware updates to your CPU.
 This used to be, "yeah, it might fix some minor bugs in a lab".   Now,
 it prevents programs from crashing:

 https://lists.archlinux.org/pipermail/arch-general/2015-April/038953.html

 (Luckily,  I  started  applying firmware updates some months ago, so I
 was to hit by this.)