ASPM

PCIe ASPM Trades Link Wake Latency for Idle Power

A PCI Express link does not need to remain at full active power while no packets are moving. Active State Power Management, commonly called ASPM, lets compatible link partners enter lower-power link states during idle periods and return to active operation when traffic resumes. The tradeoff is direct: deeper idle states can save more energy, but leaving them takes time. A system therefore balances link power against the latency added to the next transfer.