Intel E5-4650 v2 CM8063501541700 User Manual

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Intel® Xeon® Processor E5-1600/E5-2600/E5-4600 Product Families

Datasheet Volume One

The processor has three power state functions and these will be set seamlessly via the 

SVID bus using the SetPS command. Based on the power state command, the SetPS 

commands sends information to VR controller to configure the VR to improve efficiency, 
especially at light loads. For example, typical power states are:

• PS0(00h): Represents full power or active mode
• PS1(01h): Represents a light load 5 A to 20 A
• PS2(02h): Represents a very light load <5 A

The VR may change its configuration to meet the processor’s power needs with greater 
efficiency. For example, it may reduce the number of active phases, transition from 

CCM (Continuous Conduction Mode) to DCM (Discontinuous Conduction Mode) mode, 

reduce the switching frequency or pulse skip, or change to asynchronous regulation. 
For example, typical power states are 00h = run in normal mode; a command of 01h= 

shed phases mode, and an 02h=pulse skip.

The VR may reduce the number of active phases from PS0 to PS1 or PS0 to PS2 for 
example. There are multiple VR design schemes that can be used to maintain a greater 

efficiency in these different power states, please work with your VR controller suppliers 

for optimizations.

The SetPS command sends a byte that is encoded as to what power state the VR 

should transition to.

If a power state is not supported by the controller, the slave should acknowledge with 
command rejected (11b)

Note the mapping of power states 0-n will be detailed in the VR12/IMVP7 Pulse Width 
Modulation Specification

. 

If the VR is in a low power state and receives a SetVID command moving the VID up 

then the VR exits the low power state to normal mode (PS0) to move the voltage up as 

fast as possible. The processor must re-issue low power state (PS1 or PS2) command if 
it is in a low current condition at the new higher voltage. See 

 for VR power 

state transitions.