Hp Static High Performance Mode; Hp Static Low Power Mode; Hp Dynamic Power Savings Mode; Configuring Ultra Low Power State - HP AB500A - Integrated Lights-Out Advanced Technology Brief

Because Power Regulator runs from system firmware, changes between HP modes take effect
immediately. A system reboot is required when changing into or out of OS Control mode.
Not all Power Regulator modes are supported on all ProLiant servers and processor models.
Beginning with G5 servers, however, all Power Regulator modes are supported on all ProLiant 200-
series and above server models. For a detailed list of processors supported by Power Regulator,
consult the Power Regulator website at
http://www.hp.com/servers/power-regulator

HP Static High Performance mode

In Static High Performance mode, the system's processors operate continuously at the highest power
and performance state (Pmax). In this mode, neither the system's firmware nor the operating system
will ever program the processors to run in a lower power or performance state. This mode is useful for
benchmarking a server's power consumption with the power savings technology of HP Power
Regulator disabled.

HP Static Low Power mode

In Static Low Power mode, the system's processors operate continuously at the lowest power state
(Pmin). In this mode, Power Regulator programs the processors to run continuously in the low-power
state to allow the server to run at a guaranteed lower maximum power level. This feature is useful for
environments where power availability is constrained and it is critical that the server's maximum
power use be lowered.

HP Dynamic Power Savings mode

The Dynamic Power Savings mode of Power Regulator is similar in concept to Intel's Demand Based
Switching with Enhanced Intel SpeedStep® Technology and to AMD's PowerNow!, but it adds a
significant HP innovation. In HP Dynamic Power Savings mode, Power Regulator uses a ROM-based
algorithm developed by HP to monitor processor activity. It adjusts processor power use to match
performance levels to the application load. Dynamic Power Savings mode can be supported whether
or not an operating system supports Intel's Demand Based Switching or AMD's PowerNow and
regardless of which operating system the server is running. Current HP ProLiant servers enable HP
Dynamic Power Savings mode by default, so they provide significant power savings out-of-the-box
without affecting system performance.

Configuring Ultra Low Power state

The Ultra Low Power state is a Power Regulator sub-mode that is unique to AMD-based G5 ProLiant
servers and later. It is used to control which processor P-state is used for the low power state in both
HP Static Low Power Mode and HP Dynamic Power Savings mode. When Ultra Low Power state is
enabled, Power Regulator uses the lowest defined processor P-state for the low power state. When it
is disabled, the next-lowest P-state is used. Ultra Low Power state is enabled by default and can be
configured through the ROM Based Setup Utility.
This functionality was implemented to provide maximum flexibility when configuring Power Regulator
on AMD-based ProLiant servers, since the lowest P-states for the AMD processors are somewhat lower
than those of Intel processors. Testing has shown that for most processor utilization profiles, enabling
Ultra Low Power State provides the most power savings with little or no performance degradation.

OS Control mode

In OS Control mode, HP Power Regulator functionality is not directly active. Dynamic power
management for the system is managed instead by the operating system through its policy
mechanism. In this mode, the HP system BIOS ROM creates the required ACPI tables to enable the
operating system to support Intel's Demand Based Switching or AMD's PowerNow! power
4