Dell PowerEdge R820 Technical Manual page 31

User-configurable settings: An R820 thermal control design target is to minimize the

contribution of fan power to overall system power. However, with the understanding and
realization that every customer has a unique set of circumstances or expectations of the system,
in this generation of servers, we are introducing limited user-configurable settings in the iDRAC7
BIOS setup screen. For more information, see the
Dell.com/Support/Manuals
and Power Goals" on Dell.com.
Cooling redundancy: The R820 allows continuous operation with a fan failure in the system.

 Environmental specifications: The optimized thermal management makes the R820 reliable
under a wide range of operating environments as shown in the environmental specifications in
Table 27. Many configurations are also compliant under expanded operating temperature
environments, but a few are not.
Acoustical design
The acoustical design of the PowerEdge R820 reflects the following:
 Versatility: The PowerEdge R820 saves you power draw in the data center, but it also is quiet
enough for the office environment in typical and minimum configurations.
Adherence to Dell's high sound quality standards: Sound quality is different from sound power

level and sound pressure level in that it describes how humans respond to annoyances in sound,
like whistles and hums. One of the sound quality metrics in the Dell specification is prominence
ratio of a tone, which is listed in Table 18.
 Noise ramp and descent during bootup from power off: Fan speeds and noise levels ramp
during the boot process (from power off to power on) in order to add a layer of protection for
component cooling in the case that the system were not to boot properly. To keep bootup as
quiet as possible, the fan speed reached during bootup is limited to about half of full speed.
Noise level dependencies: If acoustics is important to you, you may want to make the following

configuration choices and settings for the PowerEdge R820 because they result in quieter
operation:
— iDRAC7 BIOS settings: Performance Per Watt (DAPC or OS) may be quieter than Performance
or Dense Configuration (iDRAC Settings > Thermal > Max. Exhaust Temperature or Fan speed
offset)
— Hot spare feature of power supply unit: In system default setting, the Hot Spare Feature is
disabled; acoustical output from the power supplies is lowest in this setting
However, some components cause significant but not necessarily intuitive increases in loudness
when they are installed in the R820. Contributors to acoustical output can include:
— PCIe SSD cards (such as Fusion-io)
— GPUs
— Express Flash PCIe SSDs
— 10Gb NIC
— Dell Select Network Adapter
— Dell PERC cards
— Number of installed processors
— Number of installed PCIe cards
— Number of hard drives
31 PowerEdge R820 Technical Guide
Dell PowerEdge R820 Owner's Manual
and "Advanced Thermal Control: Optimizing across Environments
on