ENERGY STAR® Program Requirements
Product Specification for
Computer Servers
Eligibility Criteria
Version 3.0

Following is the Version 3.0 ENERGY STAR Product Specification for Computer Servers. A product shallmeet all of the identified criteria if it is to earn the ENERGY STAR.

1 DEFINITIONSA) Product Types:
1) Computer Server: A computer that provides services and manages networked resources forclient devices (e.g., desktop computers, notebook computers, thin clients, wireless devices,
PDAs, IP telephones, other computer servers, or other network devices). A computer serveris sold through enterprise channels for use in data centers and office/corporate environments.
A computer server is primarily accessed via network connections, versus directly-connecteduser input devices such as a keyboard or mouse. For purposes of this specification, acomputer server must meet all of the following criteria:
A. is marketed and sold as a Computer Server;
B. is designed for and listed as supporting one or more computer server operating systems(OS) and/or hypervisors;
C. is targeted to run user-installed applications typically, but not exclusively, enterprise innature;D. provides support for error-correcting code (ECC) and/or buffered memory (including bothbuffered dual in-line memory modules (DIMMs) and buffered on board (BOB)
configurations).
E. is packaged and sold with one or more ac-dc or dc-dc power supplies; andF. is designed such that all processors have access to shared system memory and are
visible to a single OS or hypervisor.
2) Blade System: A system comprised of a blade chassis and one or more removable blade
servers and/or other units (e.g., blade storage, blade network equipment). Blade systems
provide a scalable means for combining multiple blade server or storage units in a single
enclosure, and are designed to allow service technicians to easily add or replace (hot-swap)
blades in the field.
A. Blade Server: A computer server that is designed for use in a blade chassis. A blade
server is a high-density device that functions as an independent computer server andincludes at least one processor and system memory, but is dependent upon shared blade
chassis resources (e.g., power supplies, cooling) for operation. A processor or memory
module that is intended to scale up a standalone server is not considered a Blade Server.
(1) Multi-bay Blade Server: A blade server requiring more than one bay for installation ina blade chassis.
(2) Single-wide Blade Server: A blade server requiring the width of a standard blade
server bay.

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 1 of 17

(3) Double-wide Blade Server: A blade server requiring twice the width of a standard
blade server bay.
(4) Half-height Blade Server: A blade server requiring one half the height of a standard
blade server bay.
(5) Quarter-height Blade Server: A blade server requiring one quarter the height of astandard server bay.
(6) Multi-Node Blade Server: A blade server which has multiple nodes. The blade server
itself is hot swappable, but the individual nodes are not.
B. Blade Chassis: An enclosure that contains shared resources for the operation of blade
servers, blade storage, and other blade form-factor devices. Shared resources provided
by a chassis may include power supplies, data storage, and hardware for dc power
distribution, thermal management, system management, and network services.
C. Blade Storage: A storage device that is designed for use in a blade chassis. A blade
storage device is dependent upon shared blade chassis resources (e.g., power supplies,
cooling) for operation.
3) Fully Fault Tolerant Server: A computer server that is designed with complete hardware
redundancy, in which every computing component is replicated between two nodes running
identical and concurrent workloads (i.e., if one node fails or needs repair, the second node
can run the workload alone to avoid downtime). A fully fault tolerant server uses two systems
to simultaneously and repetitively run a single workload for continuous availability in a
mission critical application.
4) Resilient Server: A computer server designed with extensive Reliability, Availability,
Serviceability (RAS) and scalability features integrated in the micro architecture of thesystem, CPU and chipset. For purposes of ENERGY STAR certification under thisspecification, a Resilient Server shall have the following characteristics:
A. Processor RAS: The processor must have capabilities to detect, correct, and contain data
errors, as described by all of the following:(1) Error recovery by means of instruction retry for certain processor faults;(2) Error detection on L1 caches, directories, and address translation buffers using parity
protection; and(3) Single bit error correction (or better) on caches that can contain modified data.
Corrected data is delivered to the recipient as part of the request completion.
B. System Recovery & Resiliency: No fewer than six of the following characteristics shall bepresent in the server:(1) Error recovery and containment by means of (a) data poison indication (tagging) andpropagation which includes mechanism to notify the OS or hypervisor to contain theerror, thereby reducing the need for system reboots and (b) containment ofaddress/command errors by preventing possibly contaminated data from beingcommitted to permanent storage;(2) The processor technology is designed to provide additional capability andfunctionality without additional chipsets, enabling the design into systems with four ormore processor sockets;(3) Memory Mirroring: A portion of available memory can be proactively partitioned suchthat a duplicate set may be utilized upon non-correctable memory errors. This can be
implemented at the granularity of DIMMs or logical memory blocks;(4) Memory Sparing: A portion of available memory may be pre-allocated to a sparefunction such that data may be migrated to the spare upon a perceived impending
failure;ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 2 of 17

(5) Support for making additional resources available without the need for a system
restart. This may be achieved either by processor (cores, memory, I/O) on-lining
support, or by dynamic allocation/deallocation or processor cores, memory, and I/O
to a partition;(6) Support of redundant I/O devices (storage controllers, networking controllers);(7) Has I/O adapters or storage devices that are hot-swappable;(8) Can identify failing processor-to-processor lane(s) and dynamically reduce the widthof the link in order to use only non-failing lanes or provide a spare lane for failover
without disruption;(9) Capability to partition the system such that it enables running instances of the OS or
hypervisor in separate partitions. Partition isolation is enforced by the platform and/or
hypervisor and each partition is capable of independently booting; or(10)Uses memory buffers for connection of higher speed processor-memory links to
DIMMs attached to lower speed DDR channels. Memory buffer can be a separate,
standalone buffer chip which is integrated on the system board or integrated on
custom-built memory cards.
C. Power Supply RAS: All power supplies installed or shipped with the server shall be
redundant and concurrently maintainable. The redundant and repairable components
may also be housed within a single physical power supply, but must be repairable without
requiring the system to be powered down. Support must be present to operate thesystem in a degraded mode.
D. Thermal and Cooling RAS: All active cooling components shall be redundant andconcurrently maintainable. The processor complex must have mechanisms to allow it tobe throttled under thermal emergencies. Support must be present to operate the system
in a degraded mode when thermal emergencies are detected in the system components.
5) Multi-node Server: A computer server that is designed with two or more independent server
nodes that share a single enclosure and one or more power supplies. In a multi-node server,
power is distributed to all nodes through shared power supplies. Server nodes in a multi-nodeserver are not designed to be hot-swappable.
A. Dual-node Server: A common multi-node server configuration consisting of two server
nodes.
6) Server Appliance: A computer server that is bundled with a pre-installed OS and application
software that is used to perform a dedicated function or set of tightly coupled functions.
Server appliances deliver services through one or more networks (e.g., IP or SAN), and are
typically managed through a web or command line interface. Server appliance hardware andsoftware configurations are customized by the vendor to perform a specific task (e.g., nameservices, firewall services, authentication services, encryption services, and voice-over-IP(VoIP) services), and are not intended to execute user-supplied software.
7) High Performance Computing (HPC) System: A computing system which is designed andoptimized to execute highly parallel applications for high performance, deep learning, or
artificial intelligence applications. HPC systems feature clustered nodes often featuring highspeed inter-processing interconnects as well as high memory capability and bandwidth. HPC
systems may be purposely built, or assembled from more commonly available computer
servers. HPC systems must meet ALL the following criteria:
A. Marketed and sold as a Computer Server optimized for higher performance computing,augmented or artificial intelligence, or deep learning applications;
B. Designed (or assembled) and optimized to execute highly parallel applications;C. Consist of multiple computing nodes, clustered primarily to increase computational
capability;

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 3 of 17

D. Includes high speed inter-processing interconnections between nodes.
8) Direct Current (dc) Server: A computer server that is designed solely to operate on a dc
power source.
9) Large Server: A resilient/scalable server which ships as a pre-integrated/pre-tested system
housed in one or more full frames or racks and that includes a high connectivity I/O
subsystem with a minimum of 32 dedicated I/O slots.
B) Computer Server Form Factors:
1) Rack-mounted Server: A computer server that is designed for deployment in a standard 19inch data center rack as defined by EIA-310, IEC 60297, or DIN 41494. For the purposes ofthis specification, a blade server is considered under a separate category and excluded fromthe rack-mounted category.
2) Pedestal/Tower Server: A self-contained computer server that is designed with PSUs,
cooling, I/O devices, and other resources necessary for stand-alone operation. The frame ofa pedestal server is similar to that of a tower client computer.
C) Computer Server Components:
1) Power Supply Unit (PSU): A device that converts ac or dc input power to one or more dc
power outputs for the purpose of powering a computer server. A computer server PSU must
be self-contained and physically separable from the motherboard and must connect to thesystem via a removable or hard-wired electrical connection.
A. Ac-Dc Power Supply: A PSU that converts line-voltage ac input power into one or more
dc power outputs for the purpose of powering a computer server.
B. Dc-Dc Power Supply: A PSU that converts line-voltage dc input power to one or more dc
outputs for the purpose of powering a computer server. For purposes of this specification,a dc-dc converter (also known as a voltage regulator) that is internal to a computer server
and is used to convert a low voltage dc (e.g., 12 V dc) into other dc power outputs for use
by computer server components is not considered a dc-dc power supply.
C. Single-output Power Supply: A PSU that is designed to deliver the majority of its rated
output power to one primary dc output for the purpose of powering a computer server.
Single-output PSUs may offer one or more standby outputs that remain active wheneverconnected to an input power source. For purposes of this specification, the total rated
power output from any additional PSU outputs that are not primary and standby outputs
shall be no greater than 20 watts. PSUs that offer multiple outputs at the same voltage as
the primary output are considered single-output PSUs unless those outputs (1) are
generated from separate converters or have separate output rectification stages, or (2)have independent current limits.
D. Multi-output Power Supply: A PSU that is designed to deliver the majority of its rated
output power to more than one primary dc output for the purpose of powering a computer
server. Multi-output PSUs may offer one or more standby outputs that remain active
whenever connected to an input power source. For purposes of this specification, thetotal rated power output from any additional PSU outputs that are not primary andstandby outputs shall be no greater than or equal to 20 watts.
2) I/O Device: A device which provides data input and output capability between a computer
server and other devices. An I/O device may be integral to the computer server motherboard
or may be connected to the motherboard via expansion slots (e.g., PCI, PCIe). Examples ofI/O devices include discrete Ethernet devices, InfiniBand devices, RAID/SAS controllers, andFibre Channel devices.
A. I/O Port: Physical circuitry within an I/O device where an independent I/O session can beestablished. A port is not the same as a connector receptacle; it is possible that a single
connector receptacle can service multiple ports of the same interface.

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 4 of 173) Motherboard: The main circuit board of the server. For purposes of this specification, themotherboard includes connectors for attaching additional boards and typically includes thefollowing components: processor, memory, BIOS, and expansion slots.
4) Processor: The logic circuitry that responds to and processes the basic instructions that drivea server. For purposes of this specification, the processor is the central processing unit
(CPU) of the computer server. A typical CPU is a physical package to be installed on theserver motherboard via a socket or direct solder attachment. The CPU package may include
one or more processor cores.
5) Memory: For purposes of this specification, memory is a part of a server external to theprocessor in which information is stored for immediate use by the processor.
6) Storage Device: A collective term for disk drives (HDDs), solid state drives (SSDs), tapes
cartridges, and any other mechanisms providing non-volatile data storage. This definition is
specifically intended to exclude aggregating storage elements such as RAID array
subsystems, robotic tape libraries, filers, and file servers. Also excluded are storage devices
which are not directly accessible by end-user application programs, and are instead
employed as a form of internal cache.
D) Other Datacenter Equipment:
1) Large Network Equipment: A device whose primary function is to pass data among various
network interfaces/ports, is mountable in a Standard Equipment Rack, supports network
management protocols (e.g. SNMP) and contains at least one of the following features:
A. Contains more than eleven (11) physical network ports.
B. Total aggregate port throughput of the product is greater than 12 Gb/s.
2) Storage Product: A fully-functional storage system that supplies data storage services toclients and devices attached directly or through a network. Components and subsystems thatare an integral part of the storage product architecture (e.g., to provide internal
communications between controllers and disks) are considered to be part of the storage
product. In contrast, components that are normally associated with a storage environment at
the data center level (e.g., devices required for operation of an external SAN) are notconsidered to be part of the storage product. A storage product may be composed ofintegrated storage controllers, storage devices, embedded network elements, software, andother devices. While storage products may contain one or more embedded processors, theseprocessors do not execute user-supplied software applications but may execute data-specificapplications (e.g., data replication, backup utilities, data compression, install agents).
3) Uninterruptible Power Supply (UPS)1: Combination of convertors, switches, and energy
storage devices (such as batteries) constituting a power system for maintaining continuity ofload power in case of input power failure.
E) Operational Modes and Power States:
1) Idle State: The operational state in which the OS and other software have completed loading,the computer server is capable of completing workload transactions, but no active workloadtransactions are requested or pending by the system (i.e., the computer server is operational,
but not performing any useful work). For systems where ACPI standards are applicable, Idle
State correlates only to ACPI System Level S0.
2) Active State: The operational state in which the computer server is carrying out work in
response to prior or concurrent external requests (e.g., instruction over the network). Active
state includes both (1) active processing and (2) data seeking/retrieval from memory, cache,1

Input power failure occurs when voltage and frequency are outside rated steady-state and transienttolerance bands or when distortion or interruptions are outside the limits specified for the UPS.

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 5 of 17

or internal/external storage while awaiting further input over the network.
F) Other Key Terms:
1) Controller System: A computer or computer server that manages a benchmark evaluation
process. The controller system performs the following functions:A. start and stop each segment (phase) of the performance benchmark;B. control the workload demands of the performance benchmark;C. start and stop data collection from the power analyzer so that power and performancedata from each phase can be correlated;
D. store log files containing benchmark power and performance information;
E. convert raw data into a suitable format for benchmark reporting, submission andvalidation; andF. collect and store environmental data, if automated for the benchmark.
2) Network Client (Testing): A computer or computer server that generates workload traffic fortransmission to a unit under test (UUT) connected via a network switch.
3) RAS Features: An acronym for reliability, availability, and serviceability features. The three
primary components of RAS as related to a computer server are defined as follows:
A. Reliability Features: Features that support a server’s ability to perform its intended
function without interruption due to component failures (e.g., component selection,
temperature and/or voltage de-rating, error detection and correction).
B. Availability Features: Features that support a server’s ability to maximize operation at
normal capacity for a given duration of downtime (e.g., redundancy [both at micro- andmacro-level]).
C. Serviceability Features: Features that support a server’s ability to be serviced without
interrupting operation of the server (e.g., hot plugging).
4) Server Processor Utilization: The ratio of processor computing activity to full-load processor
computing activity at a specified voltage and frequency, measured instantaneously or with ashort term average of use over a set of active and/or idle cycles.
5) Hypervisor: A type of hardware virtualization technique that enables multiple guest operating
systems to run on a single host system at the same time.
6) Auxiliary Processing Accelerators (APAs): An additional compute device installed in thecomputer server that handles parallelized workloads in place of the CPU. This includes, but is
not limited to, General Purpose Graphics Processing Units (GPGPUs) and Field
Programmable Gate Array (FPGA) chips. There are two specific types of APAs used inservers:
A. Expansion APA: An APA that is an add-in card installed in an add-in expansion slot (e.g.,
GPGPUs installed in a PCI slot). An expansion APA add-in card may include one or more
APAs and/or separate, dedicated removeable switches.
B. Integrated APA: An APA that is integrated into the motherboard or CPU package.
7) Buffered DDR Channel: Channel or Memory Port connecting a Memory Controller to adefined number of memory devices (e.g., DIMMs) in a computer server. A typical computer
server may contain multiple Memory Controllers, which may in turn support one or more
Buffered DDR Channels. As such, each Buffered DDR Channel serves only a fraction of thetotal addressable memory space in a computer server.

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 6 of 17

G) Product Family: A high-level description referring to a group of computers sharing one
chassis/motherboard combination that often contains hundreds of possible hardware and software
configurations. Products within a product family may differ in color.
1) Common Product Family Attributes: A set of features common to all models/configurations
within a product family that constitute a common basic design. All models/configurations
within a product family must share the following:
A. Be from the same model line or machine type;
B. Either share the same form factor (i.e., rack-mounted, blade, pedestal) or share the samemechanical and electrical designs with only superficial mechanical differences to enablea design to support multiple form factors;
C. Either share processors from a single defined processor series or share processors thatplug into a common socket type. All configurations shipped as ENERGY STAR within the
product family shall contain the same number of populated sockets used during testing. A
product family can be defined for a server with only partially populated sockets (e.g. one
processor populated in a two socket processor system) as long as the configuration(s)are tested as a separately certified product family, as required, and meet the active
efficiency limit for the number of populated sockets within that separate family.
D. Share PSUs that perform with efficiencies greater than or equal to the efficiencies at all
required load points specified in Section 3.2 (i.e., 10%, 20%, 50%, and 100% of
maximum rated load for single-output; 20%, 50%, and 100% of maximum rated load for
multi-output).
2) Product Family Tested Configurations2:
A. Low-end Performance Configuration: The combination of Processor Socket Power,
PSUs, Memory, Storage Devices, and I/O devices that represents the lowestperformance computing platform within the Product Family. This configuration shall
include the lowest processer performance per socket, as represented by the lowest
numerical value resulting from the multiplication of the core count by the frequency inGHz, offered for sale and capable of meeting ENERGY STAR requirements.3 It shall also
include a memory capacity at least equal to the number of memory channels in the server
multiplied by the smallest DIMM size offered in the family.
B. High-end Performance Configuration: The combination of Processor Socket Power,
PSUs, Memory, Storage Devices, and I/O devices that represents the highestperformance computing platform within the Product Family. This configuration shall
include the highest processer performance per socket, as represented by the highest
numerical value resulting from the multiplication of the core count by the frequency inGHz, offered for sale and capable of meeting ENERGY STAR requirements.2 It shall also
include a memory capacity equal to the value found in Equation 1 below:
Equation 1: Minimum Memory Capacity of High-end Performance Configuration
𝑀𝑒𝑚_𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦_𝐻𝑖𝑔ℎ ≥ 3 × (# 𝑜𝑓𝑆𝑜𝑐𝑘𝑒𝑡𝑠 × # 𝑜𝑓 𝑃ℎ𝑦𝑠𝑖𝑐𝑎𝑙 𝐶𝑜𝑟𝑒𝑠 × # 𝑇ℎ𝑟𝑒𝑎𝑑𝑠 𝑝𝑒𝑟 𝐶𝑜𝑟𝑒)

2

A single product configuration may be certified alone without a family.
Processor performance per socket = [# of processor cores] x [processor clock speed (GHz)], where # ofcores represents the number of physical cores and processor clock speed represents the Max TDP corefrequency as reported by SERT for a given processor.
3

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 7 of 17

C. Typical Configuration: A product configuration that lies between the Low-end
Performance and High-end Performance configurations and is representative of a
deployed product with high volume sales. It shall also include a memory capacity equal tothe value found in Equation 2 below:
Equation 2: Minimum Memory Capacity of Typical Configuration
𝑀𝑒𝑚_𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦_𝑇𝑦𝑝 ≥ 2 × (# 𝑜𝑓𝑆𝑜𝑐𝑘𝑒𝑡𝑠 × # 𝑜𝑓 𝑃ℎ𝑦𝑠𝑖𝑐𝑎𝑙 𝐶𝑜𝑟𝑒𝑠 × # 𝑇ℎ𝑟𝑒𝑎𝑑𝑠 𝑝𝑒𝑟 𝐶𝑜𝑟𝑒)

2 SCOPE
2.1
2.1.1

2.2

Included Products
A product must meet the definition of a Computer Server provided in Section 1 of this document
to be eligible for ENERGY STAR certification under this specification. Eligibility under Version 3.0
is limited to Blade-, Multi-node, Rack-mounted, or Pedestal form factor computer servers with nomore than four processor sockets in the computer server (or per blade or node in the case of
blade or multi-node servers). Products explicitly excluded from Version 3.0 are identified in
Section 2.2.

Excluded Products

2.2.1

Products that are covered under other ENERGY STAR product specifications are not eligible forcertification under this specification. The list of specifications currently in effect can be found atwww.energystar.gov/products.

2.2.2

The following products are not eligible for certification under this specification:i.

Computer Servers shipped with Integrated APAs;

ii.

Fully Fault Tolerant Servers;

iii. Server Appliances;iv. High Performance Computing Systems;v.

Large Servers;vi. Storage Products including Blade Storage; andvii. Large Network Equipment.

3 CERTIFICATION CRITERIA
3.1

Significant Digits and Rounding

3.1.1

All calculations shall be carried out with directly measured (unrounded) values.

3.1.2

Unless otherwise specified, compliance with specification limits shall be evaluated using directly
measured or calculated values without any benefit from rounding.

3.1.3

Directly measured or calculated values that are submitted for reporting on the ENERGY STAR
website shall be rounded to the nearest significant digit as expressed in the corresponding
specification limit.

3.2
3.2.1

Power Supply Requirements
Power supply test data and test reports from testing entities recognized by EPA to perform power
supply testing shall be accepted for the purpose of certifying the ENERGY STAR product.

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 8 of 17

3.2.2

Power Supply Efficiency Criteria: Power Supplies used in products eligible under this specificationmust meet the following requirements when tested using the Generalized Internal Power Supply
Efficiency Test Protocol, Rev. 6.7 (available at www.efficientpowersupplies.org). Power Supply
data generated using Rev. 6.4.2 (as required in Version 1.1), 6.4.3, 6.5, or 6.6 are acceptableprovided the test was conducted prior to the effective date of Version 3.0 of this specification.
i.

Pedestal and Rack-mounted Servers: To certify for ENERGY STAR, a pedestal or rackmounted computer server must be configured with only PSUs that meet or exceed theapplicable efficiency requirements specified in Table 1 prior to shipment.

ii.

Blade and Multi-node Servers: To certify for ENERGY STAR, a Blade or Multi-node computer
server shipped with a chassis must be configured such that all PSUs supplying power to thechassis meet or exceed the applicable efficiency requirements specified in Table 1 prior to
shipment.
Table 1: Efficiency Requirements for PSUs

3.2.3

Power Supply Type

Rated Output Power

10%
Load

20%
Load

50%
Load

100%
Load

Multi-output(Ac-Dc)All Output Levels

N/A

90%

92%

89%

Single-output(Ac-Dc)All Output Levels

83%

90%

94%

91%

Power Supply Power Factor Criteria: Power Supplies used in Computers Servers eligible under
this specification must meet the following requirements when tested using the Generalized
Internal Power Supply Efficiency Test Protocol, Rev. 6.7 (available atwww.efficientpowersupplies.org). Power Supply data generated using Rev. 6.4.2 (as required in
Version 1.1), 6.4.3, 6.5 or 6.6 are acceptable provided the test was conducted prior to theeffective date of Version 3.0.
i.

Pedestal and Rack-mounted Servers: To certify for ENERGY STAR, a pedestal or rackmounted computer server must be configured with only PSUs that meet or exceed theapplicable power factor requirements specified in Table 2 prior to shipment, under all
loading conditions for which output power is greater than or equal to 75 watts. Partners are
required to measure and report PSU power factor under loading conditions of less than 75
watts, though no minimum power factor requirements apply.

ii.

Blade or Multi-node Servers: To certify for ENERGY STAR, a Blade or Multi-node computer
server shipped with a chassis must be configured such that all PSUs supplying power to thechassis meet or exceed the applicable power factor requirements specified in Table 2 prior
to shipment, under all loading conditions for which output power is greater than or equal to
75 watts. Partners are required to measure and report PSU power factor under loading
conditions of less than 75 watts, though no minimum power factor requirements apply.

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 9 of 17

Table 2: Power Factor Requirements for PSUs
10%
20%
Power Supply Type
Rated Output Power
Load Load

50%
Load

100%
Load

Ac-Dc Multi-output

Ac-Dc Single-output

3.3
3.3.1

All Output Ratings

N/A

0.80

0.90

0.95

Output Rating ≤ 500 W

N/A

0.80

0.95

0.95

Output Rating > 500 W
andOutput Rating ≤ 1,000
W

0.65

0.80

0.95

0.95

Output Rating > 1,000
watts

0.80

0.90

0.95

0.95

Power Management Requirements
Server Processor Power Management: To certify for ENERGY STAR, a Computer Server must
offer processor power management that is enabled by default in the BIOS and/or through amanagement controller, service processor, and/or the operating system shipped with thecomputer server. All processors must be able to reduce power consumption in times of low
utilization by:i.

reducing voltage and/or frequency through Dynamic Voltage and Frequency Scaling (DVFS),orii.

enabling processor or core reduced power states when a core or socket is not in use.

3.3.2

Supervisor Power Management: To certify for ENERGY STAR, a product which offers a preinstalled supervisor system (e.g., operating system, hypervisor) must offer supervisor system
power management that is enabled by default.

3.3.3

Power Management Reporting: To certify for ENERGY STAR, all power management techniquesthat are enabled by default must be detailed in the certification submission. This requirement
applies to power management features in the BIOS, operating system, or any other origin thatcan be configured by the end-user.

3.4

Blade and Multi-Node System Criteria

3.4.1

Blade and Multi-Node Thermal Management and Monitoring: To certify for ENERGY STAR, ablade or multi-node server must provide real-time chassis or blade/node inlet temperaturemonitoring and fan speed management capability that is enabled by default.

3.4.2

Blade and Multi-Node Server Shipping Documentation: To certify for ENERGY STAR, a blade or
multi-node server that is shipped to a customer independent of the chassis must be accompaniedwith documentation to inform the customer that the blade or multi-node server is ENERGY STAR
qualified only if it is installed in a chassis meeting requirements in Section 3.4.1 of this document.
A list of certified chassis and ordering information must also be provided as part of productcollateral provided with the blade or multi-node server. These requirements may be met via either
printed materials, electronic documentation provided with the blade or multi-node server, or
information publicly available on the Partner’s website where information about the blade or multinode server is found.

3.5
3.5.1

Active State Efficiency Criteria
Active State Efficiency Reporting: To certify for ENERGY STAR, a Computer Server or Computer
Server Product Family must be submitted for certification with the following information disclosed
in full and in the context of the complete Active State efficiency rating test report:

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 10 of 17

i.

Final SERT rating tool results, which include the results files (in xml, html, and text format)
and all results-chart png files; andii.

Intermediate SERT rating tool results over the entire test run, which include the results-details
files (in xml, html, and text format) and all results-details-chart png files.

Data reporting and formatting requirements are discussed in Section 4.1 of this specification.
3.5.2

Incomplete Reporting: Partners shall not selectively report individual workload module results, orotherwise present efficiency rating tool results in any form other than a complete test report, incustomer documentation or marketing materials.

3.5.3

Active State Efficiency Requirements: Calculated Active State efficiency score (EffACTIVE) shall begreater than or equal to the minimum Active State efficiency thresholds listed in Table 3 for all
configurations submitted for certification within a product family, as well as any additional
configurations within the product family shipped as ENERGY STAR.
Equation 3: Calculation EffACTIVE

Eff ACTIVE  EXP(0.65 * ln( EffCPU )  0.30 * ln( EffMEMORY )  0.05 * ln( EffSTORAGE ))Where:▪

EffACTIVE is comprised of EffCPU, EffMEMORY and EffSTORAGE
which are defined in equations 4 through 6 below:

Equation 4: Calculation EffCPU

Eff CPU  Geomean( EffCOMPRESS , EffLU , EffSOR, EffCRYPTO , EffSORT , EffSHA256 , EffHYBRIDSSJ )Where:
▪
▪
▪
▪
▪
▪
▪

EffCOMPRESS is the calculated Compression worklet score
EffLU is the calculated LU worklet score
EffSOR is the calculated SOR worklet score
EffCRYPTO is the calculated Crypto worklet score
EffSORT is the calculated Sort worklet score
EffSHA256 is the calculated SHA256 worklet score
EffHYBRIDSSJ is the calculated Hybrid SSJ worklet score

Equation 5: Calculation EffMEMORY

Eff MEMORY  Geomean( EffFLOOD 2, EffCAPACITY 2)
Where:▪
▪

EffFLOOD3 is the calculated Flood3 worklet score
EffCAPACITY3 is the calculated Capacity3 worklet score

Equation 6: Calculation EffSTORAGE

Eff STORAGE  Geomean( EffSEQUENTIAL , EffRANDOM )Where:▪
▪

EffSEQUENTIAL is the calculated Sequential worklet score
EffRANDOM is the calculated Random worklet score

Equation 7: Calculation Effi
𝐸𝑓𝑓𝑖 = 1000
Where:
▪

𝑃𝑒𝑟𝑓𝑖
𝑃𝑤𝑟𝑖

i = Represents each workload referenced in Equations 4
through 6

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 11 of 17▪
▪

Perfi =Geometric mean of the normalized interval
performance measurements.
Pwri = Geometric mean of the calculated interval power
values.

Table 3: Active State Efficiency Thresholds for all Computer Servers
Product Type

Minimum EffACTIVE

One Installed Processor
Rack

11.0

Tower

9.4

Blade or Multi-Node9.0

Resilient

4.8

Two Installed Processors
Rack

13.0

Tower

12.0

Blade or Multi-Node14.0

Resilient

5.2

Greater Than Two Installed Processors

3.6
3.6.1

3.7
3.7.1

Rack

16.0

Blade or Multi-Node

9.6

Resilient

4.2

Idle State Efficiency Criteria
Idle State Data Reporting: Idle State power (PIDLE, PBLADE, or PNODE) shall be measured andreported, both in certification materials and as required in Section 4 for all computer server types.
In addition, for blade and multi-node products, PTOT_BLADE_SYS and PTOT_NODE_SYS shall also bereported respectively. Please see Section 3.7 for details on how to calculate PBLADE and
PTOT_BLADE_SYS, and Section 3.8 for details on how to calculate PNODE and PTOT_NODE_SYS.

Calculating Idle State Values – Blade Servers
The testing of Blade Servers for compliance with Section 3.6.1 shall be carried out under all of thefollowing conditions:i.

Power values shall be measured and reported using a half-populated Blade Chassis. Blade
Servers with multiple power domains, choose the number of power domains that is closest to
filling half of the Blade Chassis. In a case where there are two choices that are equally close
to half, test with the domain or combination of domains which utilize a higher number of Blade
Servers. The number of blades tested during the half-populated Blade Chassis test shall bereported.

ii.

Power for a fully-populated blade chassis may be optionally measured and reported, provided
that half-populated chassis data is also provided.

iii. All Blade Servers installed in the Blade Chassis shall share the same configuration(homogeneous).
iv. Per-blade power values shall be calculated using Equation 8.

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 12 of 17

Equation 8: Calculation of Single Blade Power

PBLADE 
Where:
▪
▪

3.8
3.8.1

PTOT _ BLADE _ SYS
N INST _ BLADE _ SRVPBLADE is the per-Blade Server Power, PTOT_BLADE_SYS is
total measured power of the Blade System,NINST_BLADE_SRV is the number of installed Blade Servers in
the tested Blade Chassis.

Calculating Idle State Values – Multi-Node Servers
The testing of Multi-Node Servers for compliance with Section 3.6.1 shall be carried out under allof the following conditions:i.

Power values shall be measured and reported using a fully-populated Multi-Node Chassis.

ii.

All Multi-Node Servers in the Multi-Node Chassis shall share the same configuration(homogeneous).

iii. Per-node power values shall be calculated using Equation 9.
Equation 9: Calculation of Single Node PowerPNODE Where:
▪
▪

3.9
3.9.1

PTOT _ NODE _ SYS
N INST _ NODE _ SRVPNODE is the per-Node Server Power, PTOT_NODE_SYS is total
measured power of the Multi-Node Server,
NINST_NODE_SRV is the number of installed Multi-NodeServers in the tested Multi-Node Chassis.

Other Testing Criteria
APA Requirements: For all computer servers sold with expansion APAs, the following criteria andprovisions apply:i.

For all configurations, Active State and Idle State testing shall be conducted without any
APAs installed which may be offered with the product. Where an APA relies on a separate
PCIE switch for communication between the APA and CPU, the separate PCIE card(s) or
riser(s) shall be removed for Active State and Idle State testing of all configurations.

ii.

Manufacturers shall report the model name, model number, idle power consumption, andnumber of APA devices on each APA card for each APA offered as an accessory within an
ENERGY STAR product family.

iii. The idle power for the expansion APA card shall be calculated by installing the APA
expansion card in the computer server and performing just the SERT idle test (skipping theworklet tests) and subtracting the SERT idle power measured without the APA present in thecomputer servers.
iv. Where a removable switch is required to support the expansion APA, the switch should beinstalled with the APA and included in the APA card idle measurement and calculation above.

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 13 of 17

4 STANDARD INFORMATION REPORTING REQUIREMENTS
4.1
4.1.1

Data Reporting Requirements
All required data fields in the ENERGY STAR Version 3.0 Computer Servers Qualified ProductExchange form shall be submitted to EPA for each ENERGY STAR certified Computer Server or
Computer Server Product Family.
i.

Partners are encouraged to provide one set of data for each ENERGY STAR certified productconfiguration, though EPA will also accept a data set for each certified product family.

ii.

A product family certification must include data for all defined test points in 1.G)2), as
applicable.

iii. Whenever possible, Partners must also provide a hyperlink to a detailed power calculator on
their Web site that purchasers can use to understand power and performance data for
specific configurations within the product family.
4.1.2

The following data will be displayed on the ENERGY STAR Web site through the product finder
tool:
i.

model name and number, identifying SKU and/or configuration ID;ii.

system characteristics (form factor, available sockets/slots, power specifications, etc.);

iii. system type (e.g. resilient.);
iv. system configuration(s) (including Low-end Performance Configuration, High-end
Performance Configuration, and Typical Configuration for Product Family certification);v.

power consumption and performance data from required Active and Idle State Efficiency
Criteria testing including results.xml, results.html, results.txt, all results-chart png files,
results-details.html, results-details.txt, results-details.xml, all results-details-chart png files;

vi. available and enabled power saving features (e.g., power management);vii. for product family certifications, a list of qualified configurations with qualified SKUs or
configuration IDs; andviii. for a blade server, a list of compatible blade chassis that meet ENERGY STAR certification
criteria.
4.1.3

EPA may periodically revise this list, as necessary, and will notify and invite stakeholder
engagement in such a revision process.

5 STANDARD PERFORMANCE DATA MEASUREMENT AND OUTPUTREQUIREMENTS
5.1

Measurement and Output

5.1.1

A computer server must provide data on input power consumption (W), inlet air temperature (°C),
and average utilization of all logical CPUs. Data must be made available in a published or useraccessible format that is readable by third-party, non-proprietary management software over a
standard network. For blade and multi-node servers and systems, data may be aggregated at thechassis level.

5.1.2

Computer servers classified as Class B equipment as set out in EN 55022:2006 are exempt fromthe requirements to provide data on input power consumption and inlet air temperature in 5.1.1.
Class B refers to household and home office equipment (intended for use in the domestic
environment). All computer servers in the program must meet the requirement and conditions toreport utilization of all logical CPUs.

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 14 of 17

5.2

Reporting Implementation

5.2.1

Products may use either embedded components or add-in devices that are packaged with thecomputer server to make data available to end users (e.g., a service processor, embedded poweror thermal meter (or other out-of-band technology), or pre-installed OS);

5.2.2

Products that include a pre-installed OS must include all necessary drivers and software for end
users to access standardized data as specified in this document. Products that do not include a
pre-installed OS must be packaged with printed documentation of how to access registers that
contain relevant sensor information. This requirement may be met via either printed materials,
electronic documentation provided with the computer server, or information publicly available on
the Partner’s website where information about the computer server is found.

5.2.3

When an open and universally available data collection and reporting standard becomes
available, manufacturers should incorporate the universal standard into their systems;

5.2.4

Evaluation of the accuracy (5.3) and sampling (5.4) requirements shall be completed throughreview of data from component product datasheets. If this data is absent, Partner declaration
shall be used to evaluate accuracy and sampling.

5.3

Measurement Accuracy

5.3.1

Input power: Measurements must be reported with accuracy of at least ±5% of the actual value,with a maximum level of accuracy of ±10W for each installed PSU (i.e., power reporting accuracy
for each power supply is never required to be better than ± 10 watts) through the operating range
from Idle to full power;

5.3.2

Processor utilization: Average utilization must be estimated for each logical CPU that is visible to
the OS and must be reported to the operator or user of the computer server through the operating
environment (OS or hypervisor);

5.3.3

Inlet air temperature: Measurements must be reported with an accuracy of at least ±2°C.

5.4

Sampling Requirements

5.4.1

Input power and processor utilization: Input power and processor utilization measurements mustbe sampled internally to the computer server at a rate of greater than or equal to measurement
per contiguous 10 second period. A rolling average, encompassing a period of no more than 30
seconds, must be sampled internally to the computer server at a frequency of greater than orequal to once per ten seconds.

5.4.2

Inlet air temperature: Inlet air temperature measurements must be sampled internally to thecomputer server at a rate of greater than or equal to 1 measurement every 10 seconds.

5.4.3

Time stamping: Systems that implement time stamping of environmental data shall sample
internally to the computer server data at a rate of greater than or equal to 1 measurement every
30 seconds.

5.4.4

Management Software: All sampled measurements shall be made available to externalmanagement software either via an on-demand pull method, or via a coordinated pushmethod. In either case the system’s management software is responsible for establishing thedata delivery time scale while the computer server is responsible to assuring data delivered
meets the above sampling and currency requirements.

6 TESTING
6.1
6.1.1

Test Methods
When testing Computer Server products, the test methods identified in 6 shall be used todetermine ENERGY STAR certification.

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 15 of 17

Table 6: Test Methods for ENERGY STAR Certification
Product Type orComponent
All
All
6.1.2

6.2
6.2.1

6.2.2

Test Method
ENERGY STAR Test Method for Computer Servers (Rev. Sept2018)
Standard Performance Evaluation Corporation (SPEC) mostcurrent4 Server Efficiency Rating Tool (SERT)When testing Computer Server products, UUTs must have the maximum number of Processor
Sockets populated to represent that product family during testing. All systems will be subject toactive efficiency threshold requirements based on the number of sockets populated in the system
during testing.

Number of Units Required for Testing
Representative Models shall be selected for testing per the following requirements:i.

For certification of an individual product configuration, the unique configuration that is
intended to be marketed and labeled as ENERGY STAR is considered the Representative
Model.

ii.

For certification of a product family of all product types, one product configuration for eachof the three points identified in definitions 1.G)2) within the family are considered
Representative Models. All such representative models shall have the same Common
Product Family Attributes as defined in 1.G)1).

All product configurations within a product family that is submitted for certification must meet
ENERGY STAR requirements, including products for which data is not reported.

7 EFFECTIVE DATE
7.1.1

Effective Date: This ENERGY STAR Computer Servers specification shall take effect on June 17,
2019. To certify for ENERGY STAR, a product model shall meet the ENERGY STAR
specification in effect on its date of manufacture. The date of manufacture is specific to each unit
and is the date on which a unit is considered to be completely assembled.

7.1.2

Future Specification Revisions: EPA reserves the right to change this specification should
technological and/or market changes affect its usefulness to consumers, industry, or theenvironment. In keeping with current policy, revisions to the specification are arrived at throughstakeholder discussions. In the event of a specification revision, please note that the ENERGYSTAR certification is not automatically granted for the life of a product model.

8 CONSIDERATIONS FOR FUTURE REVISIONS
8.1

Inclusion of Dc-Dc Computer Servers: EPA encourages manufacturers to work withSPEC to develop support for dc servers in SERT, so that dc computer servers may beconsidered for certification in Version 3.0.

4

For the purposes of this document, the most current SERT version will be listed in the most recently
published Servers 3.0 Clarification Memo, located on the Enterprise Servers Specification Version 3.0
website (https://www.energystar.gov/products/spec/enterprise_servers_specification_version_3_0_pd)

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 16 of 17

8.2Internal Power Supply Load Points: EPA will work with stakeholders to determine if
additional investigation is needed to address the load points used in IPS requirements, toensure they continue to reflect real-world operating conditions.

ENERGY STAR Program Requirements for Computer Servers – Eligibility Criteria

Page 17 of 17