Vol 1

Intel® Xeon® Product 2800/4800/8800 v2 Product Family 39

Datasheet Volume One, February 2014

Power Management

3.2.5.1 Package C0 State

The normal operating state for the processor. The processor remains in the normal

state when at least one of its cores is in the C0 or C1 state or when the platform has

not granted permission to the processor to go into a low power state. Individual cores

may be in lower power idle states while the package is in C0.

3.2.5.2 Package C1 State

No additional power reduction actions are taken in the package C1 state. However, if

the C1E substate is enabled, the processor automatically transitions to the lowest

supported core clock frequency, followed by a reduction in voltage. Autonomous power

reduction actions which are based on idle timers, can trigger depending on the activity

in the system.

The package enters the C1 low power state when:

• At least one core is in the C1 state.

• The other cores are in a C1 or lower power state.

3.2.5.3 Package C2 State

Package C2 state is an intermediate state which represents the point at which the

system level coordination is in progress. The package cannot reach this state unless all

cores are in at least C3.

3.2.5.4 Package C3 State

A processor enters the package C3 low power state when:

• At least one core is in the C3 state.

• The other cores are in a C3 or lower power state, and the processor has been

granted permission by the platform.

Figure 3-3. Package C-State Entry and Exit

C6C3