Specification Sheet

Power Management
72 Datasheet, Volume 1 of 2
4.2.6 Package C-States and Display Resolutions
The integrated graphics engine has the frame buffer located in system memory. When
the display is updated, the graphics engine fetches display data from system memory.
Different screen resolutions and refresh rates have different memory latency
requirements. These requirements may limit the deepest Package C-state the
processor can enter. Other elements that may affect the deepest Package C-state
available are the following:
• Display is on or off
• Single or multiple displays
• Native or non-native resolution
• Panel Self Refresh (PSR) technology
Note: Display resolution is not the only factor influencing the deepest Package C-state the
processor can get into. Device latencies, interrupt response latencies, and core C-states
are among other factors that influence the final package C-state the processor can
enter.
The following table lists display resolutions and deepest available package C-State.The
display resolutions are examples using common values for blanking and pixel rate.
Actual results will vary. The table shows the deepest possible Package C-state.System
workload, system idle, and AC or DC power also affect the deepest possible Package C-
state.
4.3 Integrated Memory Controller (IMC) Power
Management
The main memory is power managed during normal operation and in low-power ACPI
C-states.
4.3.1 Disabling Unused System Memory Outputs
Any system memory (SM) interface signal that goes to a memory in which it is not
connected to any actual memory devices (such as SODIMM connector is unpopulated,
or is single-sided) is tri-stated. The benefits of disabling unused SM signals are:
• Reduced power consumption.
• Reduced possible overshoot/undershoot signal quality issues seen by the processor
I/O buffer receivers caused by reflections from potentially un-terminated
transmission lines.
Table 4-7. Deepest Package C-State Available
S Processor Line
PSR Disabled
PC8
Notes:
1. All Deep states are with Display ON.
2. The deepest package C-state dependents on various factors, including
Platform devices, HW configuration and peripheral software.