Chapter 4: AMI BIOS
4-19
High Performance Event Timer
Select Enabled to activate the High Performance Event Timer (HPET) that produces
periodic interrupts at a much higher frequency than a Real-time Clock (RTC) does in
synchronizing multimedia streams, providing smooth playback and reducing the de-
pendency on other timestamp calculation devices, such as an x86 RDTSC Instruc-
tion embedded in the CPU. The High Performance Event Timer is used to replace
the 8254 Programmable Interval Timer. The options are
Enabled
and Disabled.
USB Device Wakeup
Select Enable to "wake-up" the system via a USB device when the system is in
S3 or S4 State. The options are Enabled and
Disabled
.
PS2 KB/MS Wake Up
Select Enable to "wake-up" the system using either the PS2 keyboard or mouse (if
equipped) when the system is in S3 (Sleep) or S4 (Hibernate) state. The options
are Enabled and
Disabled
.
ACPI Aware O/S
Enable ACPI support if it is supported by the OS to control ACPI through the Operat-
ing System. Otherwise, disable this feature. The options are
Yes
and No.
Suspend Mode
This option is used to select the ACPI State that is used for system suspend. The
options are
S1 (POS)
, S3 (STR) and Auto.
S1 (POS) - All processor caches are erased, and stops executing instructions.
Power to the CPU(s) and RAM is maintained, but RAM is refreshed.
S3 (STR) - The CPU has no power and the power supply goes on reduced power
mode. However, main memory (RAM) is still powered.
ACPI APIC Support
Select Enabled to include the ACPI APIC Table Pointer in the RSDT (Root System
Description Table) pointer list. The options are
Enabled
and Disabled.
APIC ACPI SCI IRQ
When this item is set to Enabled, APIC ACPI SCI IRQ is supported by the system.
The options are Enabled and
Disabled
.
Headless Mode
This feature is used to enable system to function without a keyboard, monitor and/
or mouse attached The options are Enabled and
Disabled
.