Technology brief
HP Common Slot power supply technology
3rd edition
Table of contents
Created September 2012.
Table 1: HP CS power supplies
Name
Input
80 PLUS Certification
Gold
HP 460W CS Gold Power Supply
HP 460W CS Platinum Power Supply
HP 460W CS Platinum Plus Power Supply
HP 750W CS Gold Power Supply
HP 750W CS Platinum Power Supply
HP 750W CS Platinum Plus Power Supply
HP 750W CS -48VDC Power Supply
HP 1200W CS Silver Power Supply
HP 1200W CS Platinum Power Supply
HP 1200W CS Platinum Plus Power Supply
HP 1200W CS -48-VDC Power Supply
100-240 VAC
100-240 VAC
100-240 VAC
100-240 VAC
100-240 VAC
100-240 VAC
-48VDC
Platinum
Platinum
Gold
Platinum
Platinum
n/a1
100-240 VAC
100-240 VAC
100-240 VAC
-48 VDC
Silver
Platinum
Platinum
n/a1
Note
All HP CS power supplies designed for AC input are 80 PLUS certified. To earn 80
PLUS certification, a power supply must be proven through independent testing
to be 80% (or greater) energy efficient when delivering 20, 50, and 100% of the
rated load capacity with a true power factor of 0.9 or greater. Power supply
ratings include 80 PLUS Bronze, 80 PLUS Silver, 80 PLUS Gold, and 80 PLUS
Platinum certification.
HP Common Slot power supplies share a common electrical and physical design that allows for installation into server
and storage platforms with a Common Slot power supply bay (Figure 1). HP Common Slot power supplies are compatible
with over 90% of HP ProLiant G6 and G7/Gen 8 servers, as well as with select HP Integrity and HP storage systems.
1 DC-DC power supplies such as the HP 1200-W CS 48-VDC power supply do not receive 80 PLUS certification.
3
Figure 1: HP platforms that support HP Common Slot power supplies over several generations of products
ProLiant DL580 and DL585 G7 servers
ProLiant DL300 G6/G7/Gen8 series &
HP x3800 Network Storage
ProLiant DL100 G6 series &
HP P4000 G2 SAN
ProLiant DL785 and DL980 servers
ProLiant ML300/100 G6 series
(ML370, ML350, ML330, ML150)
HP Common Slot
power supply
ProLiant DL1000 and DL2000 series
ProLiant SL6000 and S6500 series
ProLiant c3000 enclosure
Integrity rx2800 i2 series
The ability to use HP CS power supplies across multiple platforms simplifies maintenance for an IT department. Using a
common power supply form factor requires fewer maintenance spares and decreases inventory costs and facility space
requirements. Common Slot power supplies are qualified with specific HP products based on actual power output
requirements. These qualifications are defined in the section “Installation consideration with Common Slot power
Table 2 and Figures 2A, 2B, and 2C compares and illustrates the efficiency of HP Platinum Plus, HP Platinum, and HP
Gold CS power supplies as tested internally with the internal fans as part of the efficiency calculation. The 80 Plus
certification agency data reflected in Table 2 does not include power consumed by the fans as part of the efficiency
calculation.
4
Table 2: Operating efficiencies of 80 PLUS certified HP CS power supplies
Percent of efficiency
@ 50% load
92.43%
Power supply type
HP 460W CS Gold
@ 10% load
85.02%
86.50%
88.58%
87.58%
88.85%
89.37%
78.43%
88.74%
90.37%
@ 20% load
90.39%
91.20%
92.05%
90.58%
92.04%
92.47%
86.84%
92.53%
93.24%
@ 100% load
91.57%
93.91%
93.07%
91.54%
93.67%
93.41%
91.19%
93.21%
91.92%
HP 460W CS Platinum
HP 460W CS Platinum Plus
HP 750W CS Gold
94.37%
94.42%
92.90%
HP 750W CS Platinum
HP 750W CS Platinum Plus
HP 1200W CS Silver
94.55%
94.69%
91.75%
HP 1200W CS Platinum
HP 1200W CS Platinum Plus
94.34%
94.44%
Note
Most common load point
Figure 2A: Efficiency curves for HP CS Platinum Plus power supplies
98.0%
Peak efficiency range
for 460W supply
Peak efficiency range
for 1200W supply
Peak efficiency range
for 750W supply
96.0%
94.0%
92.0%
90.0%
88.0%
86.0%
0
200
400
600
Power
750W Platinum Plus
800
1000
1200
460W Platinum Plus
1200W Platinum Plus
5
Figure 2B: Efficiency curves for HP CS Platinum power supplies
98.0%
Peak efficiency range
for 460W supply
Peak efficiency range
for 1200W supply
Peak efficiency range
for 750W supply
96.0%
94.0%
92.0%
90.0%
88.0%
86.0%
0
200
400
460W Platinum
600
800
1200W Platinum
1000
1200
Power
750W Platinum
Figure 2C: Efficiency curves for HP CS 460W Gold, 750W Gold and 1200W Silver power supplies
98.0%
Peak efficiency range
for 460W supply
Peak efficiency range
for 1200W supply
Peak efficiency range
for 750W supply
96.0%
94.0%
92.0%
90.0%
88.0%
86.0%
0
200
400
600
800
1000
1200
Power
460W Gold
750W Gold
1200W Silver
6
Load Balanced and High Efficiency Modes
An HP ProLiant server configured with the HP 460-watt, 750-watt, or 1200-watt CS power supply supports the following
three scenarios:
A: Operating with a single supply
B: Operating with redundant supplies in Load Balanced Mode
C: Operating with redundant supplies in High Efficiency Mode
Figure 3 compares the efficiency of the HP 750-W CS Platinum Plus power supply under these three scenarios. As
indicated by Curve A, a single 750-watt power supply supporting the entire load of the server can achieve the highest
efficiency when operating in the middle range of its capacity, although redundancy is not provided.
For redundant 750-watt supplies operating in Load-Balanced Mode (the default mode), the load is shared equally
between the two supplies. As shown by Curve B, Load-Balanced Mode results in a significant efficiency penalty over
much of the server’s operating range compared to a single power supply supporting the entire load.
When High Efficiency Mode is enabled for redundant supplies, each power supply in the server is designated as either a
primary or secondary supply and the entire server load is shifted to the primary power supply. This allows the primary
power supply to operate at higher efficiency points on the load curve while the secondary power supply operates in idle
mode, providing no output power and consuming very little energy (typically two to four watts per supply). The result,
as shown by Curve C, is that High Efficiency Mode achieves efficiency levels that come close to those of a single supply
system.
Figure 3: Efficiency comparison of single and redundant HP 750W CS Platinum Plus power supplies
As indicated in Figure 3, High Efficiency Mode with 750-watt supplies is beneficial for loads up to approximately 450
watts. In general, Load-Balanced Mode offers better efficiency for loads requiring more than 60% of the primary power
supply capacity.
High Efficiency Mode is enabled through the server’s ROM-Based Setup Utility (RBSU) under System options →
Redundancy options. When enabling High Efficiency Mode, the user can specify that the odd or even power supplies will
be designated manually or automatically as secondary supplies. This flexibility allows users to balance the load across a
rack manually or automatically.
7
Right-sizing the power supply
The availability of HP CS power supplies in multiple capacities allows IT technicians to match the power supply capacity
to the actual load of a server configuration; that is, to select the right-size power supply. In addition to increased
efficiency, right-sizing the power supply also offers two immediate benefits: reducing hardware cost and avoiding
trapped power capacity.
Reducing hardware cost
Smaller capacity supplies cost less to purchase than larger capacity supplies. Nevertheless, IT infrastructure designers
often configure servers with larger-than-necessary supplies to allow for future expansion or upgrades. When
purchasing a significant number of servers, the savings from ordering only the capacities actually required can be
significant
Avoiding trapped power capacity
The amount of equipment that can be deployed in a given location, such as a rack, is in direct relation to the size of the
circuit that is provisioned. Often, more equipment can be deployed than nominally available through the use of power
capping, but that can also result in performance capping when used aggressively. Additionally, depending on local
regulations, large data centers may be required by law to size their power circuit (that is, their availability of power to
the location) based on the servers’ maximum power supply output rating or regulatory-plate rating. This method of
provisioning can quickly use up the data center power budget. Most servers, even fully configured and operating at
100% utilization, will typically require only 70% of the power supply capacity. Even if only 70% of power (at the most)
will ever be used, the data center will not be able to expand because the power circuit is trapped based on the required
method of provisioning. When using power supplies that more closely match the required power, the trapped capacity
can be reclaimed to power more equipment while staying in the same power budget.
HP Power Advisor
The HP Power Advisor utility removes much of the guesswork from estimating the power requirements of a particular
HP server configuration. Developed from actual measurement data collected from HP servers running under heavy load,
the Power Advisor allows the IT/facilities technician to build a virtual server system and accurately pre-calculate the
power needs of the server configuration without having to assemble and run the hardware.
Figure 4 shows a typical screen from a Power Advisor calculation for a ProLiant DL380p Gen8 server. The Power Advisor
allows the user to select precise configuration parameters such as processor type, memory size, and drives. As the
configuration is being made, the Power Advisor continuously calculates the “Current Wattage” and “Circuit Sizing”
requirements for the configuration. A Utilization slider control allows the user to set the projected degree of server
utilization.
Note
The Power Advisor allows users to avoid initial configuration mistakes such as
using an under-rated power supply. The Power Advisor should also be consulted
before reconfiguring a server. The HP Power Advisor can be downloaded from
As shown in Figure 4A, if a redundant supply has not been added, the Power Advisor generates a message suggesting a
power supply addition. If the server configuration exceeds the capacity of the power supply, an error message is
displayed (Figure 4B).
8
Figure 4A: Configuration display with redundancy reminder message
Figure 4B: Configuration display showing message when power supply capacities have been exceeded
The HP Power Advisor allows IT architects to choose the right size power supply for a given server configuration. This
saves money in the initial acquisition by allowing the purchase of less expensive, smaller-capacity supplies. This
efficient operation results in additional energy savings.
9
HP Power Discovery Services
As a feature of Automated Energy Optimization, HP Power Discovery Services (PDS), formerly HP Intelligent Power
Discovery is the first technology to create an automated, energy-aware network between IT systems and facilities. HP
PDS allows users to reclaim millions of dollars in wasted power capacity and downtime across data centers. HP PDS
combines the HP Intelligent Power Distribution Unit (iPDU), HP CS Platinum or Platinum Plus power supplies and HP
Insight Control software to automatically track new server installations and provide higher precision, control, and
automation to power distribution. HP PDS automatically discovers newly deployed HP servers, maps them to the power
source, verifies power redundancy and ensures all power sources are connected correctly.
When configured with HP CS Platinum or Platinum Plus power supplies, which feature an embedded serial
communication technology, HP servers can automatically provide identification information such as server name, UUID
number, and IP address to the Intelligent PDU and to HP Insight Control power management software. This reduces the
amount of time needed to configure the power distribution software and hardware. Additionally, HP PDS intuitively
detects redundant power supplies to ensure they are running on different PDUs. This helps reduce unscheduled down
time and the possibility of human error, the biggest challenges of data center management. For more information on HP
PDS refer to the website referenced in the “For More Information” section of this document.
Installation considerations with HP Common Slot power
supplies
Although the common slot power supply design is shared by a number of platforms enabling cross-platform power
supply installation, HP has qualified select ProLiant, Integrity, and HP storage products to work with specific HP CS
power supplies. An interactive online compatibility guide for HP products is referenced in the “For More Information”
section of this document. Table 3 shows which HP CS power supplies support HP Power Discovery Services. All HP CS
Platinum and Platinum Plus power supplies support HP PDS functionality.
Table 3: HP CS Power supply supporting HP Power Discovery Services
Power supply type
HP ProLiant server
460W CS Platinum
ProLiant G6/G7: DL160 , DL180 , DL360 , DL380 , DL385
460W CS Platinum Plus
ProLiant Gen8: DL160, DL320e, DL360e/DL360p, DL380e/DL380p, DL385p,
ML350e/ML350p
750W CS Platinum
ProLiant G6/G7: DL180 , DL360 , DL380 , DL385
750W CS Platinum Plus
ProLiant Gen8: DL160, DL360e/DL360p, DL380e/DL380p, DL385p,
ML350e/ML350p
1200W CS Platinum
ProLiant G7: DL380 , DL385 , DL580 , DL585 , DL980
1200W CS Platinum Plus
ProLiant Gen8: DL360e/DL360p, DL380e/DL380p, DL385p, DL560p, ML350p
10
HP ProLiant servers that support redundant power supplies only allow installation of same-type supplies. A power
supply mismatch or an unsupported power supply will result in an error indication as described in Table 4.
Table 4: HP CS power supply compatibility with HP PDS
System insight
display indication
Condition
Description
Power supply
mismatch detected
during boot
Power supply LED (all
supplies) blinking
amber
BIOS ROM will power up power supply #1 and then halt.
Power supply
mismatch detected
during runtime
Power supply LED
(added supply only)
blinking amber
iLO will detect the mismatch and not allow the added power supply to turn
on.
Unsupported power
supply detected
during boot
Power supply LED
(added supply only)
blinking amber
BIOS ROM will detect an unsupported power supply installation. BIOS ROM
will halt at POST with a failure message and will light the appropriate LED.
The LED will reset when the unsupported supply has been removed and
system is restarted.
HP CS power supplies are hot-pluggable/hot-swappable on ProLiant servers under the following conditions:
• The server must already be configured with redundant power supplies.
• The removed and replacement power supplies must be of the same type (same part number).
For all other situations, the ProLiant server should be powered down before a power supply is removed or installed.
Conclusion
The common slot power supply bay allows over 90% of the ProLiant server line to use 80 PLUS-certified power supplies.
By using IT equipment that supports common-slot power supplies, IT and facilities administrators can reduce spares
inventory costs and space requirements while reducing energy consumption costs and reclaiming data center power
capacity.
For more information
Visit the URLs listed below if you need additional information.
Resource description
Web address
HP Power Supplies
HP ProLiant servers
HP ProLiant Energy Efficient Solutions
Automated Energy Optimization
HP Power Advisor utility
80 PLUS program
HP interactive online compatibility guide
HP Intelligent Power Discovery (Power Discovery
Services)
11
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© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. The only
warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein
should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.
TC1208930, Created in September 2012
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