The Link State Power Management is a part of PCI Express Active State Power Management (ASPM). The link State of a PCIe Device is converted from L0 (on) to L1 (off) when the link is not transferring data. The hardware is automatically converted to L0 again when data is available to transfer across the link.
There are basically 2 levels of power management in the PCI Express options. The difference between these 2 options are the
power savings versus the
Latency (Time to recover from the Sleep state).
- If you select Off, there is no power savings, and the current will run regardless of what state the laptop is in. (depending on if your laptop is plugged in or not).
- On battery: Off = PCI Express will communicate even when using battery power.
- Plugged in: Off = PCI Express will communicate when plugged in as well.
- If you select Moderate Power Savings, the power savings are less, but the time to recover from the Sleep state (latency) is much shorter.
- If you select Maximum Power Savings, the power savings are greater, but the time to recover from the Sleep state (latency) is much longer.
Sometimes this mechanism cause a bit trouble during power transitions, specially during sleep. So it may be wanted to turn the Link State Power Management off, if necessary.
This tutorial will show you how to turn on or off the
PCI Express Link State Power Management in
Vista,
Windows 7, and
Windows 8.