In order to improve the energy efficiency of future computer servers, the U.S. Environmental Protection Agency (EPA) has published Draft 1, Version 3 of its Energy Star Computer Server Specification.

To be eligible for the program, a server must meet all of the following criteria:

  • 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
  • Provide 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

Excluded products include 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 Plus 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 2.

EPA table 01 (cr) Table 1: Minimum Power Supply Efficiency

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 resilient categories. Measured idle state power must be less than the calculated maximum idle state power (PIDLE_MAX) using the following equation:

EPA formula (cr)

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.

EPA table 02 (cr) Table 2: Base Idle State Power Allowance – One Socket Servers

EPA table 03 (cr) Table 3: Base Idle State Power Allowance – Two Socket Servers

EPA table 04 (cr) Table 4: Additional Idle Power Allowances for Extra Components

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 Accelerator (APA) idle state power—Version 3 reduces the power to 30 W per APA from 46 W per APA in the current version.