Filter
Top Products
Interfaces
38 Intel® Xeon® Processor E5-1600 v2/E5-2600 v2 Product Families
Datasheet Volume One of Two
2.5.2.6.1 DRAM Thermal and Power Optimization Capabilities
DRAM thermal and power optimization (also known as RAPL or “Running Average Power
Limit”) services provide a way for platform thermal management solutions to program
and access DRAM power, energy and temperature parameters. Memory temperature
information is typically used to regulate fan speeds, tune refresh rates and throttle the
memory subsystem as appropriate. Memory temperature data may be derived from a
variety of sources including on-die or on-board DIMM sensors, DRAM activity
information or a combination of the two. Though memory temperature data is a byte
long, range of actual temperature values are determined by the DIMM specifications
and operating range.
Note: DRAM related PECI services described in this section apply only to the memory
connected to the specific processor PECI client in question and not the overall platform
memory in general. For estimating DRAM thermal information in closed loop throttling
mode, a dedicated SMBus is required between the CPU and the DIMMs. The processor
PCU requires access to the VR12 voltage regulator for reading average output current
information through the SVID bus for initial DRAM RAPL related power tuning.
Table 2-6 provides a summary of the DRAM power and thermal optimization capabilities
that can be accessed over PECI on the processor. The Index values referenced in
Table 2-6 are in decimal format.
Table 2-6 also provides information on alternate inband mechanisms to access similar
or equivalent information through register reads and writes where applicable. The user
should consult the Intel® Xeon® Processor E5 v2 Product Family Processor Datasheet,
Volume Two: Registers for exact details on MSR or CSR register content.
Table 2-6. RdPkgConfig() & WrPkgConfig() DRAM Thermal and Power Optimization
Services Summary (Sheet 1 of 2)
Service
Index
Value
(decimal)
Parameter
Value
(word)
RdPkgConfig()
Data
(dword)
WrPkgConfig()
Data
(dword)
Description
Alternate
Inband
MSR or CSR
Access
DRAM
Thermal
Estimation
Configuration
Data
Read/Write
15
0x0000
DRAM Thermal
Estimation
Configuration Data
N/A Read the DRAM
Thermal
Estimation
configuration
parameters.
CSR:
MEM_TRML_ESTIMATION_
CONFIG
DRAM
Thermal
Estimation
Configuration
Data
Read/Write
15
0x0000
N/A DRAM Thermal
Estimation
Configuration
Data
Configure the
DRAM Thermal
Estimation
parameters.
CSR:
MEM_TRML_ESTIMATION_
CONFIG
DRAM Rank
Temperature
Write
18
Channel
Index &
DIMM Index
N/A Absolute
temperature in
Degrees Celsius
for ranks 0, 1, 2
& 3
Write
temperature
for each rank
within a single
DIMM.
N/A
DIMM
Temperature
Read
14
Channel
Index
Absolute
temperature in
Degrees Celsius for
DIMMs 0, 1, & 2
N/A Read
temperature of
each DIMM
within a
channel.
CSR: DIMMTEMPSTAT_[0:2]