Active State Power Management in Windows Vista
Updated: April 12, 2006
File name: PCI ASPM.doc
About This Download
Active State Power Management (ASPM) allows power to be incrementally reduced to individual serial links in a PCI Express fabric as a link becomes less active. ASPM is defined in the PCI Express base specification. Microsoft Windows Vista supports ASPM through enhancements to the PCI bus driver and Microsoft Windows power manager. Windows Vista enables or disables ASPM for a Link, based on the overall system power policy, the hardware capabilities of the Link, and the latency of the Link. Hardware performs the actual power management operations of transitioning Links between Link power states and resynchronizing Links. The configuration of the PCI Express implementation on a system affects the amount of power savings that can actually be achieved.
This paper describes how Windows Vista configures the PCI Express fabric to enable the maximum power savings. Hardware vendors and system manufacturers can use the information in this paper to design their systems to take advantage of ASPM support in Windows Vista.
Included in this paper: