1:ACPI
http://en.wikipedia.org/wiki/Advanced_Configuration_and_Power_Interface
2:What is difference between deep and deeper sleep states?
http://www.intel.com/support/processors/sb/CS-028739.htm
3:Everything You Need to Know About the CPU C-States Power Saving Modes
4:CPU Power States (C-States)
http://www.techarp.com/showarticle.aspx?artno=420&pgno=5
CPU C-states occur in the global system G0 state. Users may not notice it when they are using the computer, unless monitoring tools like CPU-Z is used to inspect the clock speed and voltage. C-state implementations are processor-specific. Mobile processors usually have more C-states than desktop processors. For example, the mobile Core 2 Duo processor (Merom) supports C0 to C4 states, whereas the desktop Core 2 Duo processor (Conroe) only supports C0 and C1 states.
C0 State (Active)
C1 State (Halt)
C2 State (Stop Grant)
C3 State (Deep Sleep)
C4 State (Deeper Sleep)
C5 State
C6 State
5:C-States In Multi-Core Processors
http://www.techarp.com/showarticle.aspx?artno=420&pgno=6
In a multi-core processor, there can be multiple C-states in each core, but only one processor C-state is enabled at one time. The processor C-state is equal to the highest C-state of any processing core. Let's say the processor C-state is Cx, and core C-state is CCx, the formula for determining the processor C-state would be :
Cx = max (CCx1, CCx2, CCx3……, CCxn)
Here are some examples :
CPU In C0 State |
CPU In C1 State |
CPU In C2 State |
|
max (CC0, CC3) |
max (CC1, CC3) |
max (CC2, CC3) |
|
CPU In C3 State |
CPU In C3 State |
CPU In C4 State |
|
max (CC3, CC3) |
max (CC4, CC3) |
max (CC4, CC4) |
CPU Power States Summary
Power State
|
Execution
|
Wake-Up Time |
CPU Power
|
Platform
|
Core Voltage
|
Cache Shrink |
Loss Of Context |
C0
|
Yes
|
0ns
|
large
|
normal
|
normal
|
no
|
no
|
C1
|
No
|
10ns
|
30%
|
normal
|
normal
|
no
|
no
|
C2
|
No
|
100ns
|
30%
|
no I/O buffer
|
normal
|
no
|
no
|
C3
|
No
|
50,000ns
|
30%
|
I/O + no snoop
|
normal
|
no
|
no
|
C4
|
No
|
160,000ns
|
2%
|
I/O + no snoop
|
C4_VID
|
yes
|
no
|
C5
|
No
|
200,000ns
|
N/A
|
N/A
|
C4_VID
|
L2 = 0KB
|
no
|
C6
|
No
|
N/A
|
N/A
|
N/A
|
C6_VID
|
L2 = 0KB
|
yes
|