IBM Intel Xeon E5-2637 49Y8125 User Manual
Product codes
49Y8125
Intel® Xeon® Processor E5-1600/E5-2600/E5-4600 Product Families
99
Datasheet Volume One
Power Management
4.3.2.3
DLL and PLL Shutdown
Self refresh, according to configuration, may be a trigger for master DLL shut-down
and PLL shut-down. The master DLL shut-down is issued by the memory controller
and PLL shut-down. The master DLL shut-down is issued by the memory controller
after the DRAMs have entered self refresh.
The PLL shut-down and wake-up is issued by the PCU. The memory controller gets a
signal from PLL indicating that the memory controller can start working again.
4.3.3
DRAM I/O Power Management
Unused signals are tristated to save power. This includes all signals associated with an
unused memory channel.
unused memory channel.
The I/O buffer for an unused signal should be tristated (output driver disabled), the
input receiver (differential sense-amp) should be disabled. The input path must be
gated to prevent spurious results due to noise on the unused signals (typically handled
gated to prevent spurious results due to noise on the unused signals (typically handled
automatically when input receiver is disabled).
4.4
DMI2/PCI Express* Power Management
Active State Power Management (ASPM) support using L1 state, L0s is not supported.
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