Intel G870 CM8062307260115 User Manual
Product codes
CM8062307260115
Datasheet, Volume 1
49
Power Management
4.3.2.3
Dynamic Power Down Operation
Dynamic power-down of memory is employed during normal operation. Based on idle
conditions, a given memory rank may be powered down. The IMC implements
aggressive CKE control to dynamically put the DRAM devices in a power down state.
The processor core controller can be configured to put the devices in active power down
(CKE de-assertion with open pages) or precharge power down (CKE de-assertion with
all pages closed). Precharge power down provides greater power savings but has a
bigger performance impact, since all pages will first be closed before putting the
devices in power down mode.
conditions, a given memory rank may be powered down. The IMC implements
aggressive CKE control to dynamically put the DRAM devices in a power down state.
The processor core controller can be configured to put the devices in active power down
(CKE de-assertion with open pages) or precharge power down (CKE de-assertion with
all pages closed). Precharge power down provides greater power savings but has a
bigger performance impact, since all pages will first be closed before putting the
devices in power down mode.
If dynamic power-down is enabled, all ranks are powered up before doing a refresh
cycle and all ranks are powered down at the end of refresh.
cycle and all ranks are powered down at the end of refresh.
4.3.2.4
DRAM I/O Power Management
Unused signals should be disabled to save power and reduce electromagnetic
interference. This includes all signals associated with an unused memory channel.
Clocks can be controlled on a per DIMM basis. Exceptions are made for per DIMM
control signals, such as CS#, CKE, and ODT for unpopulated DIMM slots.
interference. This includes all signals associated with an unused memory channel.
Clocks can be controlled on a per DIMM basis. Exceptions are made for per DIMM
control signals, such as CS#, CKE, and ODT for unpopulated DIMM slots.
The I/O buffer for an unused signal should be tristated (output driver disabled), the
input receiver (differential sense-amp) should be disabled, and any DLL circuitry
related ONLY to unused signals should be disabled. The input path must be gated to
prevent spurious results due to noise on the unused signals (typically handled
automatically when input receiver is disabled).
input receiver (differential sense-amp) should be disabled, and any DLL circuitry
related ONLY to unused signals should be disabled. The input path must be gated to
prevent spurious results due to noise on the unused signals (typically handled
automatically when input receiver is disabled).
4.4
PCI Express* Power Management
• Active power management support using L0s, and L1 states.
• All inputs and outputs disabled in L3 Ready state.
• All inputs and outputs disabled in L3 Ready state.
Table 4-7.
Targeted Memory State Conditions
Mode
Memory State with Internal Graphics
Memory State with External Graphics
C0, C1, C1E
Dynamic memory rank power down based on
idle conditions.
Dynamic memory rank power down based on
idle conditions.
C3, C6
Dynamic memory rank power down based on
idle conditions
If the graphics engine is idle, no display
If the graphics engine is idle, no display
requests, and permitted display configuration,
then enter self-refresh. Otherwise, use
dynamic memory rank power down based on
idle conditions.
Dynamic memory rank power down based on
idle conditions
If there are no memory requests, then enter
If there are no memory requests, then enter
self-refresh. Otherwise, use dynamic
memory rank power down based on idle
conditions.
S3
Self Refresh Mode
Self Refresh Mode
S4
Memory power down (contents lost)
Memory power down (contents lost)