Intel S2600KPFR Product Specifications page 136

Platform Management
9.3.14.5.2 Memory Thermal Management
The system memory is the most complex subsystem to thermally manage as it requires
substantial interactions between the BMC, BIOS, and the embedded memory controller. This
section provides an overview of this management capability from a BMC perspective.
9.3.14.5.2.1 Memory Thermal Throttling
The system supports thermal management through closed loop throttling (CLTT) with
memory with temperature sensors. Throttling levels are changed dynamically to cap throttling
based on memory and system thermal conditions as determined by the system and DIMM
power and thermal parameters. The BMC fan speed control functionality is related to the
memory throttling mechanism used.
The following terminology is used for the various memory throttling options:
Static Closed Loop Thermal Throttling (Static-CLTT): CLTT control registers are

configured by BIOS MRC during POST. The memory throttling is run as a closed-loop
system with the DIMM temperature sensors as the control input. Otherwise, the
system does not change any of the throttling control registers in the embedded
memory controller during runtime.
Dynamic Closed Loop Thermal Throttling (Dynamic-CLTT): CLTT control registers are

configured by BIOS MRC during POST. The memory throttling is run as a closed-loop
system with the DIMM temperature sensors as the control input. Adjustments are
made to the throttling during runtime based on changes in system cooling (fan speed).
9.3.14.5.3 DIMM Temperature Sensor Input to Fan Speed Control
A clamp algorithm is used for controlling fan speed based on DIMM temperatures. Aggregate
DIMM temperature margin sensors are used as the control input to the algorithm.
9.3.14.5.4 Dynamic (Hybrid) CLTT
The system will support dynamic (memory) CLTT for which the BMC firmware dynamically
modifies thermal offset registers in the IMC during runtime based on changes in system
cooling (fan speed). For static CLTT, a fixed offset value is applied to the TSOD reading to get
the die temperature; however this does not provide as accurate results as when the offset
takes into account the current airflow over the DIMM, as is done with dynamic CLTT.
In order to support this feature, the BMC firmware will derive the air velocity for each fan
domain based on the PWM value being driven for the domain. Since this relationship is
dependent on the chassis configuration, a method must be used which supports this
dependency (for example, through OEM SDR) that establishes a lookup table providing this
relationship.
BIOS will have an embedded lookup table that provides thermal offset values for each DIMM
type, altitude setting, and air velocity range (3 ranges of air velocity are supported). During
system boot BIOS will provide 3 offset values (corresponding to the 3 air velocity ranges) to
the BMC for each enabled DIMM. Using this data the BMC firmware constructs a table that
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Technical Product Specification
Revision 1.37