QuickPath Interconnect offers three power modes, called L0, L0s and L1. L0 is the mode where QPI will be fully operational. On L0s state the data wires and the circuits that drive these wires are turned off for saving energy. And on L1 everything is turned off, saving even more energy. Of course L1 state provides a higher wake-up time than L0s.

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Figure 5: QuickPath Interconnect power modes.