Desktop 4th Generation Specification Sheet

Table Of Contents

— For package C-states, the processor is not required to enter C0 state before

entering any other C-state.

— Entry into a package C-state may be subject to auto-demotion – that is, the

processor may keep the package in a deeper package C-state than requested

by the operating system if the processor determines, using heuristics, that the

deeper C-state results in better power/performance.

The processor exits a package C-state when a break event is detected. Depending on

the type of break event, the processor does the following:

• If a core break event is received, the target core is activated and the break event

message is forwarded to the target core.

— If the break event is not masked, the target core enters the core C0 state and

the processor enters package C0 state.

— If the break event is masked, the processor attempts to re-enter its previous

package state.

• If the break event was due to a memory access or snoop request,

— But the platform did not request to keep the processor in a higher package C-

state, the package returns to its previous C-state.

— And the platform requests a higher power C-state, the memory access or

snoop request is serviced and the package remains in the higher power C-

state.

The following table shows package C-state resolution for a dual-core processor. The

following figure summarizes package C-state transitions.

Table 19. Coordination of Core Power States at the Package Level

Package C-State Core 1

C0 C1 C3 C6 C7

Core 0

C0 C0 C0 C0 C0 C0

C1 C0 C1

C3 C0 C1

C3 C3 C3

C6 C0 C1

C3 C6 C6

C7 C0 C1

C3 C6 C7

Note: 1. If enabled, the package C-state will be C1E if all cores have resolved a core C1 state or higher.

Processor—Power Management

Desktop 4th Generation Intel

Core

™

Processor Family, Desktop Intel

Pentium

Processor Family, and Desktop Intel

Celeron

Processor Family

Datasheet – Volume 1 of 2 December 2013

56 Order No.: 328897-004