Service Guide

BIOS Setup Utilities
Intel
®
Server System P4000IP and Intel
®
Workstation System P4000CR Service Guide 139
5. AHCI HDD Staggered Spin-Up
Option Values: Enabled
Disabled
Help Text:
If enabled for the AHCI Capable SATA controller, Staggered Spin-Up will be
performed on drives attached to it. Otherwise these drives will all spin up at boot.
Comments: This option enables or disables Staggered Spin-up only for disk drives attached
to ports on the AHCI Capable SATA Controller. Disk drives attached to SATA/SAS ports on
the Storage Control Unit are controlled by a different method for Staggered Spin-Up and this
option does not affect them.
This option is only visible when the SATA Controller is enabled and AHCI or RAID has been
selected as the operational SATA Mode.
Staggered Spin-Up is needed when there are enough HDDs attached to the system to cause
a marked startup power demand surge when all drives start spin-up together. Since the
power demand is greatest just as the drive spinning is started, the overall startup power
demand can be leveled off by starting up each drive at a slightly different time, so the
power demand surges for multiple drives do not coincide and cause too great a power draw.
When Staggered Spin-Up is enabled, it does have a possibility of increasing boot time if there
are many HDDs attached, because of the interval between starting drives spinning. However,
that is exactly the scenario in which Staggered Spin-Up is most needed, because the more
disk drives attached, the greater the startup demand surge.
Setting the external eSATA connector Enabled (when available) does not invalidate the
Staggered Spin-Up option, although there may be less need for Staggered Spin-Up in a
system configured for eSATA use.
6. AHCI Capable RAID Options