Memory Throttling; Acpi Power Control - Intel S7000FC4UR Technical Product Specification

Intel® Server System S7000FC4UR TPS
3.3.5

Memory Throttling

Memory throttling is the ability of the chipset to reduce bandwidth of the FBDIMMs when their
generated heat exceeds the normal thermal threshold. Each FBDIMM has an internal
temperature sensor on its Advanced Memory Buffer (AMB). Temperature readings from all
FBDIMM AMBs are monitored by the BMC and used to drive a Closed Loop Thermal Throttling
(CLTT) scheme.
As a fallback to CLTT, an Open Loop Thermal Throttling (OLTT) scheme is also available on the
server system. Each Memory riser has a temperature-sensing device that provides the
difference between the left and right sides of the DIMMs. This difference estimates the heat
generated by the DIMMs and is continuously monitored by the BMC.
In both cases, depending on memory riser temperature readings, memory may be throttled back
and fans nearby to the memory riser(s) may be boosted. Whenever this temperature reaches
the upper critical threshold, the BMC requests the AMB on the DIMMs to enable DIMM
throttling. Memory throttling is also enabled when the system chassis intrusion sensor is
engaged and in the event of a system fan failure or removal.
3.3.6

ACPI Power Control

The main board supports ACPI S0, S1, S4 and S5 system/sleep states.
The S0 system state is the normal power on state and is required for normal system
operation.
The S1 sleep state is a lower power state where the processor stops executing
instructions.
The S4 state, also called Suspend to Disk, is a "soft-off" state (like S5), whereby all of
the Operating System Contents are stored to the hard drive.
The S5 system state is the normal power off state (or "soft-off") and is required in order
to perform certain maintenance tasks.
When the system is operating in ACPI mode, the operating system retains control of the power
of the system. During ACPI mode, operating system policy determines the entry methods and
wakeup sources for each system/sleep state. An ACPI-enabled operating system generates a
System Management Interrupt (SMI) to request that the system enable ACPI support. The BIOS
responds to the SMI by communicating to the BMC that ACPI support is required.
3.3.6.1 S1 Sleep State Support
During the S1 Sleep State, the following events take place.
The front panel power LED blinks at a rate of 1 Hz with a 50% duty cycle (not controlled
by the BMC).
If enabled via the Set ACPI Configuration Mode command, the server board fans are set
to sleep speed as specified in the associated OEM TControl SDR for each fan domain.
Otherwise, fan control is the same as for ACPI S0 state. The DIMM temperature sensors
do not contribute to the fan speed control algorithm.
The watchdog timer is stopped.
Revision 1.0
Main Board Server Management
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