The Intel Skylake and Kaby Lake discovered a critical bug, leading to «unpredictable behavior»
The Intel Skylake and Kaby Lake discovered a critical error. It is associated with the implementation of multithreaded execution and HyperThreading is manifested in all the processors on the specified microarchitecture: mobile, desktop and server.
The manufacturer describes the error in the document SKZ7/SKW144/SKL150/SKX150/SKZ7/KBL095/KBW095 as follows: «Under certain conditions, short cycles of less than 64 commands using the registers AH, BH, CH or DH and the corresponding extended registers (e.g., RAX, EAX, AX, or AH) may cause unpredictable system behavior. This occurs only when both active logical processor per physical processor».
The error can be fixed with a firmware update that is distributed as an update to UEFI. In other words, the presence of a hotfix for a specific motherboard or PC ready depends on their manufacturer. As a temporary solution you can prevent HyperThreading in the UEFI setup.