Good afternoon,
The latest version of Windows 10, 1903, seems to pose compatibility problems with previous Intel CPU microcodes, on Z370.
If the microcode replacement was done through a BIOS update, OC capabilities are altered.
If the microcode update is done dynamically through the loading of mcupdate_GenuineIntel.dll during the OS initialization, then there seem to be two cases: if the file provided with the 1903 installation is used, the CPU can no longer be overclocked, whereas if a previous version is used, the OS fails to load, and also cannot identify the cause of the issue, so one has to start the computer in recovery mode, launch the terminal, and delete mcupdate_GenuineIntel.dll.
So far, I had been using a version of mcupdate_GenuineIntel.dll prior to Spectre/Meltdown mitigations, but is seems to ne longer be possible. The only remaining option, to preserve the original performances of the CPU, is to delete the file in order to use the microcode from the BIOS update (using the version prior to the integration of Intel fixes by Asus). I wonder if the structure of the files including the microcodes changes through Windows 10 has been modified, preventing the OS from using previous versions.
