Since ACPI controls power, issues with sleep/hibernate are ACPI issues.

But deep inside Luma’s silicon soul, there was a government. And its name was ACPI.

And deep inside the ACPI x64-based PC, the committee went back to its silent, endless work—governing the voltage, policing the interrupts, and ensuring that when the user closed the lid, the machine didn't die… it just dreamed.

Specifically, it signifies that your computer is using a and follows the Advanced Configuration and Power Interface (ACPI) standard for managing energy and hardware configuration. What Does "ACPI x64-based PC" Actually Mean?