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HGST boosts energy efficiency efforts with 'green' HDDs

Posted: 18 Dec 2007 ?? ?Print Version ?Bookmark and Share

Keywords:energy efficiency? green HDD? IT industry power consumption?

Wong: The trend toward the 'greening' of IT will continue to be a driving force behind IT product development efforts as PC and server OEMs build products to comply with global energy-rating programs.

By Jim Wong
Hitachi Global Storage Technologies

With the explosive growth of the Internet, digital computing and global IT infrastructures, the rise of large-scale data centers has led to an increasing awareness of their impact on power consumption. Correspondingly, the millions of consumer electronics in use today, including PCs and laptops, only add to the drain on power infrastructures. As a result, what was once largely the domain of home appliances!develop?ing energy-efficient washers and dryers, heaters and refrigerators!has now become a much larger concern for the IT industry.

The continued development in the IT industry has led to the increasing awareness of the technologies' impact on power consumption. Millions of consumer electronics, including PCs and laptops, only add to the drain on power infrastructures, As a result, what was once largely the domain of home appliances!developing energy-efficient washers and dryers, heaters, and refrigerators!has now become a much larger concern for the IT industry.

With concerns about decreasing oil reserves, energy price spikes and global warming, the IT industry has begun to place greater emphasis on reducing power consumption in data centers and in the hardware used by business customers.

Contributing to the energy conservation efforts, Hitachi Global Storage Technologies (Hitachi GST) has introduced the Deskstar P7K500 desktop hard drive, which is touted to offer the lowest power consumption among hard drives in its class. The P7K500 improves its operational power consumption by 40 percent over the previous generation, positively impacting total PC system power requirements.

Data center, PC focus
To date, the primary focus in the IT industry has been on power consumption within the data center. More companies are opting to locate data centers near sources of inexpensive energy, such as hydroelectric power. In an August 2007 report to the U.S. Congress, the Environmental Protection Agency (EPA) recommended a series of efficiency opportunities and policies that could drive a potential $4 billion savings in annual electricity costs related to data centers.

In addition, PC power consumption is a significant expense for corporations and, in July 2007, the EPA released its ENERGY STAR 4.0 specification addressing this issue. The ENERGY STAR rating has been more closely associated with major home appliances and heating and cooling systems. The previous ENERGY STAR 3.0 specification for PCs only addressed "sleep" power and not the actual power during use. Thus, nearly all PCs, including powerful gaming systems, could easily meet the requirements. This disparity resulted in an inability to differentiate energy-efficient products from standard or even power-guzzling ones.

The new ENERGY STAR 4.0 specification calls for an 80 percent minimum power-supply efficiency and sets maximum values for standby, sleep and idle power for desktop PCs that vary depending on the performance level of the system. Tier-1 specifications in effect in 2007 are designed so that approximately 25 percent of PCs will meet requirements. A Tier-2 specification, to be released on July 1, 2009, is expected to set additional standards for PCs that do not meet the strict Tier-1 requirements.

PCs that meet the new ENERGY STAR 4.0 requirements will become increasingly popular with corporations and government agencies. Corporations may choose to purchase ENERGY STAR PCs as part of their "green" initiatives. The U.S. government signed an executive order on January 24, 2007, mandating that federal agencies must purchase PCs that meet ENERGY STAR 4.0 requirements. Similarly, the European Parliament voted on July 10, 2007 to apply energy-efficiency criteria no less stringent than ENERGY STAR requirements for the purchase of all public sector office equipment, including PCs, within the European Union.

Reduced power consumption
Hitachi GST's desktop HDDs have incorporated Advanced Power Management capabilities to reduce power consumption, beginning with the Deskstar 120GXP hard drive, which was six product generations ago. With the introduction of the Deskstar P7K500 drive, Hitachi GST has taken power efficiency one step further while maintaining 7200 RPM performance.

The Deskstar P7K500 hard drive's power consumption provides a 40-percent improvement over previous-generation products by reducing power in both idle and active modes. This reduction was achieved by using the same SoC used in Hitachi's Travelstar 2.5-inch mobile product line that offers low power to maximize battery life in notebook PCs. The SoC incorporates Hitachi Voltage Efficiency Regulator Technology, which utilizes switching regulators in place of the less-power-efficient linear regulators in the voltage reduction processes. Also included in the SoC is a more power-efficient module for the serial ATA and parallel ATA interfaces.

Power data for 50 GB Deskstar P7K500

Together with the new technologies incorporated into the Deskstar P7K500 HDD, Hitachi GST's Advanced Power Management capabilities have reduced the overall power consumption of the HDD. Through the use of the company's patented load/unload technology, the P7K500 allows for additional power reductions:

  • Unload idle!The heads are safely unloaded to the ramp and the servo is shut off; this mode delivers power savings of 11 percent better than idle mode.3

  • Low RPM idle!The heads are safely unloaded to the ramp, the servo is shut off and the spindle motor RPM is reduced; this setting achieves power savings of 44 percent better than idle mode.

    When Advanced Power Management is enabled, the hard drive can automatically enter the lower-power idle states at intervals based on the time since the host system last accessed the hard rive. The drive can transition from normal idle (3.6W power) to unload idle (3.2W) to low RPM idle (2.0W) during periods of inactivity and return to normal operation automatically whenever the host system accesses it again. These transitions to lower-power idle states are done without intervention from the host system.

    Power margin
    However, the largest benefit of reducing the power consumption of the HDD in a desktop PC comes not from the savings in operating cost, but from the additional power margin in designing to the strict ENERGY STAR 4.0 requirements on idle power. Designing a 250GB Deskstar P7K500 into this system with 3.6W idle power instead of this typical HDD with 7W idle power eliminates 3.4W of nonproductive power that can instead be used to provide additional features and functions on the PC. As an example, a systems designer could add an additional optical drive (1.3W), increase the system RAM by 1GBbyte DDR2 SDRAM (1.5W) and still have 0.8W of power that could be allocated to additional ports on the motherboard.

    Typical power partitioning for a 50W ENERGY STAR system

    Path to green electronics
    The trend toward the "greening" of IT will continue to be a driving force behind IT product development efforts as PC and server OEMs build products to comply with global energy-rating programs. Every component within these systems must also be specified to contribute to reductions in overall power consumption.

    About the author
    Jim Wong
    is a senior product strategist for Hitachi Global Storage Technologies. He can be contacted at

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