Intel® Server System R2000WF Product Family Technical Product Specification
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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.
4.2.1.6
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,
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.
4.2.1.7
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
1
CPU margin sensors
2, 4, 5
DIMM thermal margin sensors
2, 4
Exit air temperature sensor
1, 7, 9
PCH temperature sensor
3, 5
Onboard Ethernet controller temperature sensors
3, 5
Add-in SAS module temperature sensors
3, 5
PSU thermal sensor
3, 8
CPU VR temperature sensors
3, 6
DIMM VR temperature sensors
3, 6
BMC temperature sensor
3, 6
Global aggregate thermal margin sensors
7
Hot swap backplane temperature sensors
Intel® OCP module temperature sensor (with option installed)
Intel® SAS module (with option installed)
Riser card temperature sensors (2U systems only)
Intel® Xeon Phi™ coprocessor (2U system only with option installed)
Notes
:
1
For fan speed control in Intel chassis
2
Temperature margin to max junction temp
3
Absolute temperature
4
PECI value or margin value
5
On-die sensor
6
Onboard sensor
7
Virtual sensor
