@MaLd0n Another way that OC can break Windows is with ACPI patches that unconditionally change ACPI. I do the IRQ fixes with SSDTs instead of OC ACPI patches (e.g., I don't use config.plist > ACPI > Patch for IRQ fixes) so that I can condition them on _OSI("Darwin"). Why don't the ACPI patches like "TMR IRQ 0 Fix" affect Windows? Just asking, because I don't know - not challenging your wisdom. Thank you.
EDIT: Although, after I started disabling HPET, I no longer needed IRQ fixes.