12th Generation Intel® Core™ Processors Datasheet, Volume 1 of 2
Low-Power Idle States
When the processor is idle, low-power idle states (C-states) are used to save power. More power savings actions are taken for numerically higher C-states. However, deeper C-states have longer exit and entry latencies. Resolution of C-states occurs at the thread, processor IA core, and processor package level.
While individual threads can request low-power C-states, power saving actions only take place once the processor IA core C-state is resolved. processor IA core C-states are automatically resolved by the processor. For thread and processor IA core C-states, a transition to and from C0 state is required before entering any other C-state.