Figure 13 shows a 750W power supply unit extended from an R720 system.
The PowerEdge R720 and R720xd support up to two AC or DC power supplies with 1 + 1 redundancy, auto sensing, and auto-switching capability.
Dell PSUs have achieved Platinum efficiency levels as shown in Table 20.
Form factor Output Class
Redundant 86mm
495W
750W
Platinum
Platinum
1100W Platinum+
1100W DC 1 Gold
1 1100W DC power supply available Q2 2012.
10%
82.0%
82.0%
89.0%
80.0%
Efficiency targets by load
20%
90.0%
90.0%
93.0%
88.0%
50%
94.0%
94.0%
94.5%
92.0%
100%
91.0%
91.0%
92.0%
88.0%
Thermal management of PowerEdge R720 and R720xd delivers high performance for the right amount of cooling to components at the lowest fan speeds across a wide range of ambient temperatures from 10°C to 35°C (50°F to 95°F) and to extended ambient temperature ranges (see
Table 32) . The benefits to you are lower fan power consumption (lower server system power and
data center power consumption) and greater acoustical versatility. The PowerEdge R720 is quiet enough to be used in an office environment in typical and minimum configurations, and the R720xd can also operate at a similar level in certain configurations.
The thermal design of the PowerEdge R720 and R720xd reflect the following:
Optimized thermal design: The system layout is architected for optimum thermal design.
System component placement and layout are designed to provide maximum airflow coverage to critical components with minimum expense of fan power.
36 PowerEdge R720 and R720xd Technical Guide
Comprehensive thermal management: The thermal control system regulates the fan speed based on several different responses from all system-component temperature sensors, as well as inventory for system configurations. Temperature monitoring includes components such as processors, DIMMs, chipset, the inlet air ambient, hard disk drives, NDC, and GPU.
Open and closed loop thermal fan speed control: Open loop thermal control uses system configuration to determine fan speed based on inlet air ambient temperature. Closed loop thermal control method uses feedback temperatures to dynamically determine proper fan speeds.
User-configurable settings: With the understanding and realization that every customer has unique set of circumstances or expectations from the system, in this generation of servers, we have introduced limited user-configurable settings residing in the iDRAC7 BIOS setup screen. For more information, see the PowerEdge R720 and R720xd Systems Owner’s Manual on
Support.Dell.com/Manuals and “Advanced Thermal Control: Optimizing across Environments and Power Goals” on Dell.com
.
Cooling redundancy: The R720 and R720xd allow N+1 fan redundancy, allowing continuous operation with one fan failure in the system.
Environmental specifications: The optimized thermal management makes the R720 and R720xd
reliable under a wide range of operating environments as shown in Table 32.
The acoustical design of the PowerEdge R720 and R720xd reflect the following:
Versatility: The R720 and R720xd save you power draw in the data center but are also quiet enough for office environment in typical and minimum configurations. Compare the values for
LpA in Table 21 and Table 22 for these configurations, and note that they are lower than ambient
measurements of typical office environments. You may find that the system is sufficiently quiet where the sound it emits blends into the environment.
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 21 and Table 22.
Noise ramp and descent at 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 event that the system were not to boot properly. In order to keep the bootup process 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, several configuration choices and settings are important to consider:
-
For lower acoustical output, use a small number of lower rotational-speed SATA hard drives, nearline SAS hard drives, or non-rotational devices like SSDs. 15k hard drives generate more acoustic noise than that of lower rotational-speed hard drives, and noise increases with number of hard drives.
- Fan speeds and noise may increase from baseline factory configurations if certain profiles are changed by the user or the system configurations are updated. The following is a list of items that impact fan speeds and acoustical output:
> 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).
37 PowerEdge R720 and R720xd Technical Guide
>
>
>
>
>
The quantity and type of PCIe cards installed: This affects overall system acoustics.
Installation of more than two PCIe cards results in an increase in overall system acoustics.
Utilization of a GPU card: This results in an increase in overall system acoustics.
PCIe controller-based SSD drives: Drives such as Express flash drives and Fusion-io ® cards require greater airflow for cooling, and result in significantly higher noise levels.
Systems with an H310 PERC: This configuration may be quieter than those with an H710
PERC with battery backup. However, higher noise levels result when a system is configured as non-RAID.
Hot spare feature of power supply unit: In the system default setting, the Hot Spare
Feature is disabled; acoustical output from the power supplies is lowest in this setting.
Table 21 and Table 22 detail the acoustical performance for the R720 and R720xd.
Configuration
(23 ± 2°C ambient)
CPUs Hard drives
Power supply unit
Memory
PCI card/HDD controller
Operating mode
L
WA
-UL 1
(bels)
L pA
2
(dBA)
Prominent tones 3
Minimum
Typical
1
2
1 x 250GB
SATA (7.2k)
6 x 300GB
SAS (10K)
1 x
495W
2 x
750W
1 x
8GB
8 x
8GB
1 x PERC
H310
1 x PERC
H710,
1 x GbE
NIC
Idle
Stressed 4
Idle
Stressed 4
4.0
4.1
4.4
4.5
20
20
25
26
None
None
None
None
Configuration
(23 ± 2°C ambient)
CPUs Hard drives
Power supply unit
Memory
PCI card/HDD controller
Operating mode
L
WA
-UL 1
(bels)
L pA
2
(dBA)
Prominent tones 3
Minimum 1
1 x 250GB
SATA (7.2k)
1 x
495W
1 x
8GB
1 x PERC
H310
Idle 4
Stressed 5
Idle 4
4.7
4.8
28
28
None
None
Typical 2
14 x 300GB
SAS (10K)
2 x
750W
8 x
8GB
1 x PERC
H710,
1 x GbE
NIC
Stressed 5
4.8
5.0
28
30
None
None
1 LwA – UL is the upper limit sound power levels (LwA) calculated per section 4.4.1 of ISO 9296 (1988) and measured in accordance to ISO 7779 (2010).
2
LpA is the average A-weighted sound pressure level from the four bystander positions calculated per section 4.3 of
ISO9296 (1988) and measured in accordance with ISO7779 (2010). The system is placed in a half rack enclosure (base of system is 25 cm above reflective floor).
3 Prominent tone: Criteria of D.6 and D.11 of ECMA-74 11th ed. (2010) are followed to determine if discrete tones are prominent. The system is placed in a half rack enclosure (base of system is 75 cm above reflective floor) and acoustic transducer is at front bystander position, ref ISO7779 (2010 Section 8.6.2).
4
Idle: Reference ISO7779 (2010) definition 3.1.7; system is running in its OS but no other specific activity.
5
Stressed processor: An operating mode per ISO7779 (2010) definition 3.1.6. The software SPECPower at 50% loading is activated to stress the processors.
For more information on Dell’s acoustical design, see the Dell Enterprise Acoustics white paper.
38 PowerEdge R720 and R720xd Technical Guide
