5
Power Management Scheme
EIST will function only if the operating system is using an adaptive power management scheme. The fol-
lowing table shows the relationship between power scheme and the control policy used.
For more information about processor performance control, go to:
http://www.microsoft.com/whdc/system/pnppwr/powermgmt/ProcPerfCtrl.mspx
Power Scheme - Adaptive or Not
An adaptive power scheme allows the operating system to dynamically adjust performance of a processor
(frequency and voltage) according to the amount of processor usage. You can determine whether a
power management scheme is adaptive. If a power management scheme has not been modified, it will
have the default processor performance control policy. However, a modified power scheme will not pro-
vide external notification regarding its current control policy.
To verify processor performance control policy, perform the following steps:
1.
Click
Start
>
Run
.
2.
Type
CMD
.
3.
Type
powercfg /query.
The system displays the current power configuration.
Processor Throttle <AC>
and
Processor
Throttle <DC>
indicate which control policy is implemented when the system is using AC power or bat-
tery power.
Power Scheme
AC Power
DC Power
Home/Office Desk
None
Adaptive
Portable/Laptop
Adaptive
Adaptive
Presentation
Adaptive
Degrade
Always On
None
None
Minimal Power Management
Adaptive
Adaptive
Max Battery
Adaptive
Degrade