Intel SE8500HW4 User Manual
Page 45
Intel® Server Board Set SE8500HW4
Server Management
Revision 1.0
Intel order number D22893-001
33
Fan settings are configurable via SDRs to allow for the specific cooling requirements needed by
system integrators. A test command can also be issued to manually force the fan speed to a
selected value, overriding any other control or policy.
Ambient system temperature is determined from address 0x90 on private I
2
C bus 0, which for
the Intel
®
Server Platform SR4850HW4 and Intel
®
Server Platform SR6850HW4 is a sensor on
the SCSI Backplane Board. The temperature value used by server management is this sensor
reading minus 3°C. This sensor address is hard-coded in the BMC and not configured via an
SDR value.
5.2.1 Memory
Throttling
Memory throttling is the ability of the chipset to reduce bandwidth of the DIMMs when their
generated heat exceeds the normal thermal threshold. Each Memory Board has a temperature
sensing device that provides the difference between left and right side of the DIMMs. This
difference estimates the heat generated by the DIMMs and is continuously monitored by the
BMC. Depending on Memory Board temperature readings, memory may be throttled back and
fans nearby to the Memory Board(s) may be boosted. Whenever this temperature reaches the
upper critical threshold, the BMC requests the XMB on the Memory Board to enable DIMM
throttling. Memory throttling is also enabled when the system intrusion sensor is engaged and in
the event of a system fan failure or removal.
5.2.2 Processor
Throttling
Processor throttling is the ability of the processor to reduce core speed, and thereby its heat,
when generated heat exceeds normal thermal thresholds. The processor can throttle itself, and
under the following conditions the Intel
®
Server Board Set SE8500HW4 will request a processor
to throttle:
A processor voltage regulator (onboard or module) asserts a thermal trip
The power consumption threshold of the system is crossed
BMC requests all processors to throttle
In the Intel
®
Server Board Set SE8500HW4 the BIOS will force all processors into a throttled
condition when any one processor enters this state. Processor throttling is reset after a system
reboot.