ENERGY STAR® Program Requirements
Product Specification for
Computers
Final Draft Test Method
Rev. Sep-2018

1 OVERVIEW
The following test method shall be used for determining product compliance with requirements in the
ENERGY STAR Specification for Computers.

2 APPLICABILITY
ENERGY STAR test requirements are dependent upon the feature set of the product under evaluation.
The following guidelines shall be used to determine the applicability of each section of this document:▪

The procedure in Section 6 shall be conducted on all eligible products that are covered under thescope as defined in Section 2 of the ENERGY STAR Final Draft Eligibility Criteria for Computers.

▪

The procedure in Section 7 shall be conducted only on eligible Workstation Computer products.

3 DEFINITIONS
Unless otherwise specified, all terms used in this document are consistent with the definitions in the
ENERGY STAR Specification for Computers.

4 TEST SETUP
4.1 Test Setup and Instrumentation
Test setup and instrumentation for all portions of this procedure shall be in accordance with therequirements of International Electrotechnical Commission (IEC) standard, IEC 62301, “Household
Electrical Appliances – Measurement of Standby Power” Edition 2.0, 2011-01, Section 4, “General
Conditions for Measurements”, unless otherwise noted in this document. In the event of conflicting
requirements, the ENERGY STAR test method shall take precedence.
A) Input Power: Products intended to be powered from alternating current (ac) mains shall be connected
to a voltage source appropriate for the intended market, as specified in Table 1 and Table 2.

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Table 1: Input Power Requirements for Products with
Nameplate Rated Power Less Than or Equal to 1500 watts (W)Voltage

VoltageTolerance

Maximum
Total
Harmonic
Distortion

Frequency

Frequency
Tolerance

North America, Taiwan

115 volts(V) ac+/- 1.0 %2.0 %60 hertz(Hz)+/- 1.0 %Europe, Australia, New Zealand

230 V ac+/- 1.0 %

2.0 %

50 Hz

+/- 1.0 %Japan

100 V ac+/- 1.0 %2.0 %50 Hz or
60 Hz+/- 1.0 %MarketTable 2: Input Power Requirements for Products with
Nameplate Rated Power Greater Than 1500 W

Voltage

VoltageTolerance

Maximum
Total
Harmonic
Distortion

Frequency

Frequency
Tolerance

North America, Taiwan

115 V ac+/- 4.0 %

5.0 %

60 Hz

+/- 1.0 %Europe, Australia, New Zealand

230 V ac+/- 4.0 %

5.0 %

50 Hz

+/- 1.0 %Japan

100 V ac+/- 4.0 %5.0 %50 Hz or
60 Hz+/- 1.0 %MarketB) Ambient Temperature: Ambient temperature shall remain between 18 C and 28 C, inclusive, for theduration of the test.
C) Relative Humidity: Relative humidity shall remain between 10% and 80%, inclusive, for the duration of
the test.
D) Light Measuring Device (LMD): All LMDs shall meet the following specifications:
1) Accuracy: ± 2% (± 2 digits) of the digitally displayed value; and
2) Acceptance Angle: 3 degrees or less.
The overall tolerance of LMDs is found by taking the absolute sum of 2%of the targeted screen
luminance and a 2 digit tolerance of the displayed value’s least significant digit. For example, if thescreen luminance value is 90 candela per meter squared (cd/m2) and the LMD’s least significant digit
is a tenth of one cd/m2, 2% of 90 cd/m2 would be 1.8 cd/m2 and a 2 digit tolerance of the leastsignificant digit would be 0.2 cd/m2. Thus, the displayed value would need to be 90 ± 2 cd/m2 (1.8
cd/m2 + 0.2 cd/m2).
Note: The term “nit” is sometimes used instead of the official SI unit cd/m2. One nit is equivalent to
one cd/m2.
E) Power Meter: Power meters shall possess the following attributes:
1) Crest Factor:a) An available current crest factor of 3 or more at its rated range value; andb) A bound on the current range of 10 milliamperes (mA) or less.
2) Minimum Frequency Response: 3.0 kilo-hertz (kHz)3) Minimum Resolution:a) 0.01 W for measurement values less than 10 W;

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Page 2 of 9b) 0.1 W for measurement values from 10 W to 100 W; andc) 1.0 W for measurement values greater than 100 W.
4) Measurement Accuracy: Measurement uncertainty as introduced by the instrument that measures
the input power to the unit under test (UUT), including any external shunts.
a) Power measurements with a value greater than or equal to 0.5 W shall be made with anuncertainty of less than or equal to 2% at the 95% confidence level.
b) Power measurements with a value less than 0.5 W shall be made with an uncertainty of lessthan or equal to 0.01 W at the 95% confidence level.

5 TEST CONDUCT
5.1 Guidance for Implementation of IEC 62623
The Test Conduct shall be carried out according to the requirements in IEC 62623, “Desktop andNotebook Computers – Measurement of Energy Consumption” Edition 1.0, 2012-10 (IEC 62623 Ed. 1.0,
2012-10) reference with the following guidance.

A) Thin Clients and Workstations shall be configured in a manner identical to Desktops (non-integrated)
unless otherwise specified. Slates/Tablets shall be configured in a manner identical to Notebooks
unless otherwise specified. Portable All-In-One Computers shall be configured in a manner identicalto Integrated Desktops unless otherwise specified.
1) Thin Clients shall run intended terminal/remote connection software during all tests.
Note: DOE removed the reference to small scale servers as these products are no longer in scope for
ENERGY STAR.
B) Wake on LAN (WoL) settings shall be in as shipped condition for testing Sleep Mode and Off Mode.
C) For models that do not offer a Sleep Mode enabled by default, Section 6.2 shall measure power in thelowest-latency user-activated mode or state that preserves machine state and is enabled by default.
1) If no such state separate from Long Idle State or Off Mode exists, the measurement in
Section 6.2 shall be skipped.
D) For Long Idle Mode Testing (Section 6.3), the UUT shall be allowed no more than 20 minutes fromthe point of ceased user input before measurements must be started. If any default settings cause the
UUT to enter Long Idle after 20 minutes, begin taking measurements when the UUT has reached the
20 minute mark. Display sleep settings shall be set to default for Long Idle Mode Testing.
E) For Alternative Low Power Mode Testing (Section 6.3), the UUT shall be allowed no more than 20
minutes from the point of ceased user input before measurements must be started. If any default
settings cause the UUT to enter the Alternative Low Mode after 20 minutes, begin taking
measurements when the UUT has reached the 20 minute mark. Display sleep settings shall be set todefault for Alternative Low Power Mode Testing. When conducting the test in section 6.3, replace all
instances of “long idle mode” with “alternative low power mode”, and apply the definition of alternative
low power mode from the ENERGY STAR Specification for Computers.
F) For Short Idle Mode Testing (Section 6.4), the UUT shall be allowed no more than five minutes fromthe point of ceased user input before measurements must be taken. Display sleep settings shall bedisabled for Short Idle Mode Testing. If any other default settings cause the UUT to exit Short Idle
during the measurement time, extend the settings so that the UUT remains in short idle for theduration of the measurement. The short idle test can either be conducted one time or multiple
times. If conducted multiple times, then the average of all runs should be reported.

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Note: DOE is proposing to allow multiple runs of the short idle test for flexibility in case of cyclicalbehaviors of the UUT in short idle. DOE requests feedback on this approach.
G) Desktops, Integrated Desktops, Notebook Computers, Portable All-In-One Computers , andSlates/Tablets shall be tested for Idle, Sleep, and Off Mode with Full Network Connectivity(“Proxying”) features using the as shipped setting.
H) Cellular network connections shall be disabled for testing. Additionally, Bluetooth should be left asshipped.
I)

It is permitted to use hardware or software to disable the battery for testing. Any software used todisable the battery must be built into the operating system or must be bundled with the system as
shipped. Instructions to run this software needs to be publicly available (e.g. listed on a website).
This hardware or software can only disconnect the battery from the system; no extra power
management features can be turned on by this hardware or software. When using this option, it canbe verified that the software disconnect is only disabling the battery by performing a comparison test.
Measure long idle with the battery connected (i.e. without using the hardware or software disconnect)
for one or more full cycles per IEC 62301, section B.2.3, and verify that this measurement isapproximately equal to the measurement with the software disconnect.
Any hardware or software used to disable the battery needs to be reported.

Note: DOE is allowing the use of a hardware or software option to disable the battery. Additional
requirements are listed to ensure that only the battery is being disabled for the test procedure. DOE
anticipates revisiting this issue under Version 8.0.
J) If the UUT is demonstrating cyclical behavior during the long idle, alternative low power mode, sleep
mode, or off mode measurement, it is permissible, but not required, to use an extended measurement
capturing one or more full cycles per IEC 62301, section B.2.3.
Note: DOE is allowing an optional use of a longer power measurement to accurately capture cyclicalbehavior that may not be measured with the standard 5-minute measurement. DOE requests commenton this additional language and anticipates revisiting this issue under Version 8.0.

5.2 Preparing Display Luminance of Notebooks, Integrated Desktops,
Slates/Tablets and Portable All-In-One ComputersA) Before performing any tests, disable display dimming, display Sleep Mode, Computer Sleep Mode,and automatic brightness control (ABC) in the Computer settings. Document all settings that werechanged from the default configuration.
1) If ABC cannot be disabled, position a light source such that at least 300 lux directly enters theABC sensor.
B) Display the three vertical bar video signal as defined in section 3.2.1.3 of IEC 60107-1, “Methods ofmeasurement on receivers for television broadcast transmissions – Part 1: General conditions –Measurements at radio and video frequencies” Edition 3.0, 1997 (IEC 60107-1 Ed. 3.0, 1997). The
three bar image shall be configured using the default image display application.
C) Devices with a cold cathode fluorescent lamp (CCFL) backlight shall warm-up for at least 30 minutes.
All other displays shall warm-up for at least 5 minutes.
D) With the LMD, measure the luminance in the center of the display.
E) Calibrate the UUT display brightness to the closest brightness setting that is at least 90 cd/m2 for
Notebook Computers, at least 150 cd/m2 for Integrated Desktop Computers, Portable All-In-One
Computers and Slates/Tablets. If the UUT’s brightest setting cannot achieve the specified brightness,then set the UUT display to the brightest setting.

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F) The display shall be configured with the ENERGY STAR test image, which can be found here1. For
Desktops, Integrated Desktops, Notebook Computers and Portable All-In-One Computers it may be
set as the “desktop background” (wallpaper) or shown via an image display application. The image
shall be scaled to completely fill the display area. For Slates/Tablets, the display shall be configured
with the default image display application.
G) Optional setting for units with multiple integrated displays. Configure all displays in the same way
using the previous steps. The displays do not have to be configured sequentially (i.e. warmup times
can be done simultaneously for all displays). For notebook computers, all displays must be set to theclosest brightness setting that is at least 90 cd/m2 for every display. For Integrated Desktop
Computers, Portable All-In-One Computers and Slates/Tablets, all displays must be set to the closest
brightness setting that is at least 150 cd/m2 for every display.
H) For all testing specified in Section 6, the UUT shall not be rebooted or restarted until after the power
measurements for Long Idle Mode and Short Idle Mode tests are taken.
I)

Slate/Tablet and Portable All-In-One Computers shall be tested with a docking station only if it isshipped with the product and is the only way to power the device mains.

6 TEST PROCEDURES FOR ALL PRODUCTS
6.1 UUT Preparation
UUT preparation shall be performed according to IEC 62623, Ed.1.0, 2012-10, Section 5.2: Test Setup;with the additional guidance in Section 5 of this document.

6.2 Sleep Mode Testing
Sleep Mode power shall be measured according to IEC 62623, Ed.1.0, 2012-10, Section 5.3.3:
Measuring Sleep Mode; with the additional guidance in Section 5 of this document.

6.3 Long Idle Mode TestingLong Idle Mode power shall be measured according to IEC 62623, Ed.1.0, 2012-10, Section 5.3.4:
Measuring Long Idle Mode; with the additional guidance in Section 5 of this document.

6.4 Short Idle Mode Testing
Short Idle Mode power shall be measured according to IEC 62623, Ed.1.0, 2012-10, Section 5.3.5:
Measuring Short Idle Mode; with the additional guidance in Section 5 of this document.

6.5 Off Mode Testing
Off Mode power shall be measured according to IEC 62623, Ed.1.0, 2012-10, Section 5.3.2: Measuring
Off Mode; with the additional guidance in Section 5 of this document.

6.6 Additional Testing For Reporting
For Notebook Computers, repeat the Short Idle test with the display brightness set to the closest settingthat is at least 150 cd/m2 for all displays.

1

https://www.energystar.gov/ia/partners/images/ComputerTestingImage.bmp

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7 TEST PROCEDURES FOR WORKSTATIONS
7.1 Maximum Power Test
The maximum power for Workstations is found by the simultaneous operation of two industry standard
benchmarks: Linpack to stress the core system (e.g., processor, memory, etc.) and SPECviewperf®
(latest available version for the UUT) to stress the system’s Graphics Processing Unit (GPU). This test
shall be repeated three times on the same UUT, and all three measurements shall fall within a ± 2%
tolerance relative to the average of the three measured maximum power values. The average powershould be used for qualification and/or TEC calculations.

Note: Workstations may certify configurations using Microsoft Windows® OS as a proxy for Linux for the
maximum power test, as SPEC does not currently support a version of SPECviewperf® capable ofrunning on the Linux OS.

Additional information on these benchmarks, including free downloads, can be found at the following
locations as specified in Table 3.

Table 3: Benchmark Information for Maximum Power Test

BenchmarkWebsite

Linpack

http://www.netlib.org/linpack/

SPECviewperf

http://www.spec.org/benchmarks.html#gpc

A) UUT Preparation:
1) Connect a power meter capable of measuring true power to an ac line voltage source set to theappropriate voltage/frequency combination for the test. The meter shall have all the attributes
listed in Section 4.1 E). The meter shall also store and output the maximum power measurement
reached during the test or be capable of another method of determining maximum power.
2) Plug the UUT into the measurement power outlet on the meter. No power strips or uninterruptible
power supply (UPS) units shall be connected between the meter and the UUT.
3) Record the ac voltage.
4) Boot the UUT and, if not already installed, install Linpack and SPECviewperf as indicated on theabove Websites.
5) Set Linpack with all the defaults for the given architecture of the UUT and set the appropriate
array size “n” for maximizing power draw during the test.
6) Ensure all technical guidelines relevant to running the benchmark set by the Standard
Performance Evaluation Corporation (SPEC) organization for running SPECviewperf have beenmet.
7) For additional information regarding Linpack setup, see Section 9.1 Typical Linpack Starting
Parameters.
B) Maximum Power Testing:1) Set the meter to begin accumulating true power values at a rate greater than or equal to one
reading per second, and begin taking measurements.
2) Run SPECviewperf and as many simultaneous instances of Linpack as needed to fully stress thesystem. Recommended setup information can be found in Section 9.1 C).

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3) Accumulate power values until SPECviewperf and all Linpack instances have completed running.
Record the maximum power value attained during the test.
4) The following data shall also be recorded:a) Value of “n” (the array size) used for Linpack;b) Number of simultaneous copies of Linpack run during the test;c) Version of SPECviewperf run for test;d) All compiler optimizations used in compiling Linpack and SPECviewperf; ande) A precompiled binary for end users to download and run both SPECviewperf and Linpack.
These can be distributed either through a centralized standards body such as SPEC, by theoriginal equipment manufacturer (OEM), or by a related third party.

7.2 Benchmark Test
The benchmark test shall be performed by running both benchmarks listed below separately. The UUT
shall be rebooted before testing with each benchmark. Additional information on these benchmarks,
including downloads, can be found at the following locations specified in Table 4. All testing shall be
performed with the latest available version of the benchmarks.

Table 4: Information for Benchmark Testing

BenchmarkWebsite

Linpack

http://www.netlib.org/linpack/

SPECviewperf

http://www.spec.org/benchmarks.html#gpc

A) UUT Preparation:
1) The UUT shall be setup identical to Step 1) through Step 4) of Section 7.1 A)
2) If not already installed, install the benchmark as indicated on the websites listed in Table 4.
3) Configure the benchmark as specified in Section 7.2 B).
4) Time Measurement: Time measurements may be performed with a standard stopwatch or othertime keeping device with a resolution of at least 1 second.
B) Benchmark Configurations:1) Linpacka) Configure the Linpack settings identically to the maximum power workstation test (e.g. Follow
Step 5) and Step 7) of Section 7.1 A)).
b) Run as many simultaneous instances of Linpack as needed to fully stress the system.
Recommended settings would be to set the number of simultaneous instances of Linpackequal to the number of logical and/or physical CPU cores of the system.
2) SPECviewperfa) Configure the settings identically to the maximum power workstation test (e.g. Follow Step 6)of Section 7.1 A)).
C) Benchmark Testing:1) Set the meter to begin accumulating true power values at a rate of greater than or equal to one
reading per second and begin power and time measurement.
2) Execute the benchmark.

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Page 7 of 93) Stop time measurement and accumulate power values for the entire duration of the benchmarkrun.
4) The following data shall be reported:a) Linpacki.

Value of “n” (the array size) used for Linpack;ii.

Number of instances of Linpack simultaneously run on the system;iii. All compiler options used in compiling Linpack;iv. Energy consumed over the duration of the test; andv.

Linpack output file in text format which contains system performance in floating point
operations per second (Flops) in addition to other Linpack parameters (e.g. number oftests, problem size, etc.).

b) SPECviewperfi.

Version of SPECviewperf used;ii.

All compiler optimizations used in compiling SPECviewperf;

iii. Duration of the test;
iv. Energy consumed over the duration of the test; andv.

All files and folders present in the Result folder of SPECviewperf suite shall be reported.

8 REFERENCES
A) IEC 62301 Edition 2.0 2011-01, Household electrical appliances – Measurement of standby power.
B) IEC 60107-1 Edition 3.0 1197-04, Methods of measurement on receivers for television broadcast
transmissions – Part 1: General Considerations – Measurements at radio and video frequencies.
C) IEC 62623 Edition 1.0 2012-10, Desktop and notebook computers – Measurement of energy
consumption

9 APPENDIX: BENCHMARK PARAMETERS
9.1 Typical Linpack Starting Parameters
Below are some typical starting values for the use of Linpack for testing Workstations. These values arestarting points and not meant to be binding. The tester is free to use the settings most advantageous totheir UUT. Platform and Operating System (OS) will have a significant impact on the applicability of thesestarting values. The below assumes Linux as the test OS.
A) Number of equations (problem size): See Equation.
B) Leading dimensions of array: See Equation.
The matrix size (the combination of number of equations and leading dimensions of array) should be
the maximum size that will fit in the Random Access Memory (RAM) on the machine.
This AWK script will calculate matrix size on a Linux machine:

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awk 'BEGIN {
printf "Maximum matrix dimension that will fit in RAM on this machine: "}/^MemTotal:/ {print int(sqrt(($2*1000)/8)/1000) "K"}' /proc/meminfo
Use the output of this to determine what matrix size to input for both the "Number of equations" and"Leading dimensions of array" inputs. The “Number of equations” will be equal to the printed output.
The “Leading dimensions of the array” will be the output rounded up to the nearest multiple of eight.
This calculation can be most easily calculated by taking the memory size, in bytes, of the UUT(denoted as m) and substituting m in Equation 1.

m 1000
81000
Equation 1: Memory Size Calculation

C) Number of trials: c - 1 where c equals the number of logical and/or physical CPU cores of the system.
The tester needs to determine which
 is more advantageous for the unit. The -1 leaves one core open
for use by SPECviewperf.
D) Data alignment value: Typically four with Linux systems. The best value to use is the page size
boundary of the OS.

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