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.)