Intel C2550 FH8065401488912 Data Sheet

Intel

®

 Atom™ Processor C2000 Product Family for Microserver

September 2014

Datasheet, Vol. 2 of 3

Order Number: 330061-002US

159

When one or more of the processor cores are active, the SoC power management 

adjusts the operating conditions as needed to reflect both the objectives of the 

operating system and the physical temperature and power-related constraints. In most 

cases, objectives are met by adjusting the target frequency of each active core. The 

SoC power management adjusts each core target clock speed to a discrete operating 

point. The discrete steps between these operating points correspond to core clock 

ratios.

As the target frequency is changed, the operating voltage is set to the highest sVID 

request from all modules. Several factors contribute to the active operating point of a 

core at any given instant:

• Operating System (OS) P-State requests for that core
• P-State requests of the other cores in the package
• The P-State selection model
• The current temperature of each core
• Any available turbo modes
• Previous P-states and C-states
• Any other factors

Based on a snapshot of these factors, the SoC determines a target ratio and associated 

frequency for each core as well as a package target. The resolved package operating 

point is the highest requested operating point of any of the cores in the package, after 

all factors are taken into account.

When the core is idle (in a lower-power C-State than C0), its voting rights may be 

suspended based on the Energy Performance BIAS MSR setting (0x1b0), and the core 

either acts as a slave to the operating voltage specified by other cores or has its 

voltage removed by turning off its power gate.

When resolving the operating point of an individual core, the various contributing 

factors are weighed independently to come up with three ratio targets:

• Software-initiated request (OS P-State request),
• Thermally-constrained operating target, and
• Power-constrained operating target.

The upper and lower bounds of these targets are weighed and prioritized to come up 

with a final ratio resolution for each core and the sections.

Additional active-state power management features change the power processor core 

characteristics without changing the operating voltage and frequency. For the most 

part, these features provide legacy power management functionality, and are 

superseded by the newer voltage and frequency scaling capabilities of today’s 

processors.