EPA Begins Revising Computer Server Program Spec

Fri, 09/23/2016 - 11:22 -- MrGreen

The U.S. Environmental Protection Agency (EPA) has begun drafting version 3 of its ENERGY STAR efficiency specification for computer servers. As with the current version, a server must meet all of the following criteria to be part of this program:

  • Marketed and sold as a computer server
  • Packaged and sold with at least one AC-DC or DC-DC power supply
  • Designed for and listed as supporting at least one or more computer server operating systems and/or hypervisors
  • Targeted to run user-installed enterprise applications
  • Provides support for ECC and/or buffered memory
  • Designed so all processors have access to shared system memory and are visible to a single OS or hypervisor

The following products are excluded from the program: fully fault tolerant servers, server appliances, high performance computing systems, large servers, storage products including blade storage, and network equipment.

Major elements of draft 1 include:

  • More stringent power supply efficiency 80+ Platinum efficiency levels are being proposed for power supplies shipped with the server, as shown in Table 1 below. Power Factor requirements stay the same as the current version.

Table 1. Minimum Power Supply Efficiency

Power Supply Type Rated Output Power Minimum PSU Efficiency
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%


  • Idle state power requirement revision The EPA is proposing tighter idle state power limits for all one and two socket servers, including multi-node, blade and resilient1 categories. Measured idle state power must be less than the calculated maximum idle state power using the following equation:

Where PIDLE_MAX = maximum idle state power requirement, PBASE = base idle power allowance as specified in tables 2 and 3, and PADDL_i = idle state power allowance for additional components, as specified in table 4.

Table 2. Base Idle State Power Allowance – One Socket Servers

Category Resilient Base Idle State Power Allowance, PBASE (W)
A No 37
B Yes 130


Table 3. Base Idle State Power Allowance – Two Socket Servers

Category Blade or Multi-node Resilient Base Idle State Power Allowance, PBASE (W)
C No No 85
D Yes No 105
E No Yes 297


Table 4. Additional Idle Power Allowances for Extra Components

System Characteristic Applies To: Additional Idle Power Allowance (W)
Additional Power SuppliesPower supplies installed explicitly for power redundancy10 W per power supply
Storage DevicesPer installed storage device4 W per storage device
Additional MemoryInstalled memory > 4GB 0.25 W per GB
Additional Buffered DDR ChannelInstalled buffered DDR, Channels > 8 (Resilient Server Only)4 W per buffered DDR channel
Additional I/O DevicesInstalled devices > 2 ports of ≥ 1 Gbit, onboard Ethernet<1 Gbit: No Allowance,
= 1 Gbit: 2 W per active port,
>1 Gbit and <10 Gbit: 4 W per active port,
≥10 Gbit.: 8 W per active port


  • The development of active state power metrics The EPA intends to include active state efficiency requirements in version 3. Discussions are on-going with stakeholders to develop potential active state efficiency requirements.
  • Lower Auxiliary Processing Accelerator2 (APA) idle state power Version 3 requirement reduces the power to 30 W per APA from 46 W per APA in the current version.

Computer server related questions can be sent to servers@energystar.com. Copies of the proposed draft and recent stakeholder meeting materials can be downloaded here.

1. A resilient server is a computer server designed with extensive reliability, availability, serviceability, and scalability features. See Appendix B of the program specification draft for more information. 2APAs are computing expansion add-in cards that can be installed in general purpose expansion slots.