Nominal Fan Speed; Thermal And Acoustic Management; Thermal Sensor Input To Fan Speed Control - Intel R1000SPO Series Technical Product Specification

4.2.4

Nominal Fan Speed

A fan domain's nominal fan speed can be configured as static (fixed value) or controlled by the state of one
or more associated temperature sensors.
OEM SDR records are used to configure which temperature sensors are associated with which fan control
domains and the algorithmic relationship between the temperature and fan speed. Multiple OEM SDRs can
reference or control the same fan control domain; and multiple OEM SDRs can reference the same
temperature sensors.
The PWM duty-cycle value for a domain is computed as a percentage using one or more instances of a
stepwise linear algorithm and a clamp algorithm. The transition from one computed nominal fan speed
(PWM value) to another is ramped over time to minimize audible transitions. The ramp rate is configurable by
means of the OEM SDR.
Multiple stepwise linear and clamp controls can be defined for each fan domain and used simultaneously.
For each domain, the BMC uses the maximum of the domain's stepwise linear control contributions and the
sum of the domain's clamp control contributions to compute the domain's PWM value, except that a
stepwise linear instance can be configured to provide the domain maximum.
Hysteresis can be specified to minimize fan speed oscillation and to smooth fan speed transitions. If a
Tcontrol SDR record does not contain a hysteresis definition, for example, an SDR adhering to a legacy
format, the BMC assumes a hysteresis value of zero.
4.2.5

Thermal and Acoustic Management

This feature refers to enhanced fan management to keep the system optimally cooled while reducing the
amount of noise generated by the system fans. Aggressive acoustics standards might require a trade-off
between fan speed and system performance parameters that contribute to the cooling requirements and
primarily memory bandwidth. The BIOS, BMC, and SDRs work together to provide control over how this
trade-off is determined.
This capability requires the BMC to access temperature sensors on the individual memory DIMMs.
Additionally, closed-loop thermal throttling is only supported with buffered DIMMs.
4.2.6

Thermal Sensor Input to Fan Speed Control

The BMC uses various IPMI sensors as input to the fan speed control. Some of the sensors are IPMI models
of actual physical sensors whereas some are "virtual" sensors whose values are derived from physical
sensors using calculations and/or tabular information.
The following IPMI thermal sensors are used as input to fan speed control:
Front Panel Temperature Sensor

CPU Margin Sensors

DIMM Thermal Margin Sensors

Exit Air Temperature Sensor

PCH Temperature Sensor

Add-In Intel SAS Module Temperature Sensors

PSU Thermal Sensor

CPU VR Temperature Sensors

DIMM VR Temperature Sensors

BMC Temperature Sensor

Global Aggregate Thermal Margin Sensors

Intel® Server System R1000SPO Product Family TPS
1
2,4,5
2,4
1, 7, 9
3,5
3, 8
5
5
3, 6
6
7
32