hari2202 :
Pinhedd :
ACPI stands for Advanced Configuration and Power Interface. It's a standard method for controlling power states of the PC and attached peripherals. This is what allows for sleep mode and many other things.
x64 implies that the system is running with the x86 64 bit extensions, either AMD64 or EM64T.
is it a hardware ?
It's a standard that is implemented by the operating system, firmware (BIOS/UEFI), microprocessor, and attached peripherals. Significant parts of it are exposed as data tables and functions in the system firmware along with device-specific interfaces. It shows up in device manager because it has driver behaviour.