Skylake, Kaby Lake chips have a crash bug with hyperthreading enabled
Under certain conditions, systems with Skylake or Kaby Lake processors can crash due to a bug that occurs when hyperthreading is enabled. Intel has fixed the bug in a microcode update, but until and unless you install the update, the recommendation is that hyperthreading be disabled in the system firmware.
All Skylake and Kaby Lake processors appear to be affected, with one exception. While the brand-new Skylake-X chips still contain the flaw, their Kaby Lake X counterparts are listed by Intel as being fixed and unaffected.