PC power management

PC power management

PC power management refers to the mechanism for controlling the power use of personal computer hardware. This is typically through the use of software that puts the hardware into the lowest power demand state available. It is an aspect of Green computing.

A typical office PC might use on the order of 90 watts when active (approximately 50 watts for the base unit, and 40 watts for a typical LCD screen); and three to four watts when ‘asleep’. Up to 10% of a modern office’s electricity demand might be due to and PCs and monitors.[1]

While some PCs allow low power settings, there are many situations, especially in a networked environment, where processes running on the computer will prevent the low power settings from taking effect. This can have a dramatic effect on energy use that is invisible to the user. The monitor may have gone into standby mode, and the PC may appear to be idle, but operational testing has shown that on any given day an average of over 50% of an organisation's computers would fail to go to sleep, and over time this happened to over 90% of the machines.[1]

Contents

Windows 'Insomnia' (Sleepless PCs)

The Windows power management system is based upon an idle timer. If the computer is idle for longer than the preset timeout then the PC may be configured to sleep or hibernate. The user may configure the timeout using the Control Panel. Windows uses a combination of user activity and CPU activity to determine when the computer is idle.

Applications can temporarily inhibit this timer by using the SetThreadExecutionState API.[2] There are legitimate reasons why this may be necessary such as burning a DVD or playing a video. However, in many cases applications can unnecessarily prevent power management from working. This is commonly known as Windows 'Insomnia' and can be a significant barrier to successfully implementing power management.

Common causes of 'insomnia' include:

  • Legacy or non-power management aware applications
  • Open file handles on remote computers
  • Faulty mice which can cause pointer drift. This makes the operating system believe that a user is present
  • Scheduled maintenance tasks causing significant CPU activity

Software solutions

There is a significant market in third-party PC power management software offering features beyond those present in the Windows operating system.[3][4][5] available. Most products offer Active Directory integration and per-user/per-machine settings with the more advanced offering multiple power plans, scheduled power plans, anti-insomnia features and enterprise power usage reporting. Notable vendors include 1E NightWatchman.[6][7], Data Synergy PowerMAN (Software)[8], Faronics Power Save[9][10] and Verdiem SURVEYOR[11].


Using this type of energy management tool on an organisation's network has been demonstrated to save on average 200 kg of CO2 emissions per PC per year, and generate $36 per PC per year in energy savings.[12] An organisation such as a large office, with 4,000 employees, would be able to make CO2 emissions savings of over 800 tonnes and about $140,000 per year in energy savings. A large corporation with 50,000 employees could save 10,000 tonnes of CO2 and about $1.7 million per year in energy costs[13].

UK Carbon Reduction Commitment incentives

With the Carbon Reduction Commitment (CRC) regulations coming into force in 2010, many businesses will be required to "budget" for their emissions of Carbon Dioxide. Organisations will be required to buy allowances to cover their CO2 emissions; top performers will receive financial rewards; and poor performers will be penalized.

The CRC uses electricity consumption as a means for determining which organizations fall under the new regulations, and covers all organizations with an electricity consumption of greater than 6,000 MWH per year (equivalent to emissions of approximately 1,280 tonnes CO2 per year from electricity use). Organizations must purchase allowances to cover all of their CO2 emissions with the exception of transport.[14] The CRC will incentivise energy efficiency and greenhouse gas emissions reduction in the non-energy intensive sector of business and industry.

As well as driving supply side measures to reduce the carbon intensity of energy consumed, the CRC will also provide big incentives for demand side energy efficiency. Once quick wins have been identified, attention will become more and more focused on harder to reach energy losses. These include energy losses distributed across organizations due to the organizations physical infrastructure, and also the way it uses energy consuming devices.

By looking at IT operations and energy use, proven energy management tools demonstrate that the CRC target of 4 million tonnes of CO2 emissions reduced by 2020 is readily achievable.

See also

  • IT energy management

References

  1. ^ a b Sleepless of Seattle; Why Windows Power Management Doesn't Always Work, Mark Blackburn, Strategy Analyst, 1E, January 2009
  2. ^ "SetThreadExecutionState Function". Microsoft. http://msdn.microsoft.com/en-us/library/aa373208(VS.85).aspx. Retrieved 2010-06-07. 
  3. ^ "Power Management Software for Windows Workstations". http://www.windowsitpro.com/article/buyers-guide/Power-Management-Software-for-Windows-Workstations-Buyers-Guide.aspx. 
  4. ^ "Energy Star Commercial Packages List". http://www.energystar.gov/index.cfm?c=power_mgt.pr_power_mgt_comm_packages. 
  5. ^ The Headmasters' and Headmistresses' Conference. "HMC: A Practical Guide to Sustainable Building for Schools". http://www.hmcsustainability.org.uk/energy.html. 
  6. ^ "PC Power Management Solutions". http://itmanagersinbox.com/1399/pc-power-management-solutions. 
  7. ^ "Why use software NightWatchman to turn your PCs off?". http://features.techworld.com/green-it/3546/why-use-software-nightwatchman-to-turn-your-pcs-off/. 
  8. ^ "University of Oxford Low Carbon Project: Energy and the networked computing environment". http://projects.oucs.ox.ac.uk/lowcarbonict/conferences/conf-2.htm#providers. 
  9. ^ Bisetty, Krisendra (April 29, 2008). "Powering down and ramping up" (print). Business in Vancouver (Vancouver, BC, Canada): p. B3. http://www.faronics.com/news/PR_BIV_052008.pdf. 
  10. ^ Francis, Russ (September 29, 2005). "B.C. Hydro adds energy-efficient software to online catalogue". ITBusiness.ca. http://www.itbusiness.ca/it/client/en/Home/News.asp?id=36913&bSearch=True. 
  11. ^ "1E upgrades NightWatchman, seeks to bring powermanagement to SMEs: Competitive landscape". http://www.1e.com/Downloads/Articles/Published/451%20-%201E%20-%20Market%20Development-020309.pdf. 
  12. ^ "How Dell Does IT: Energy Efficiency, Dell Cuts energy costs by up to 40% with a new power management plan". http://www.dell.com/content/topics/global.aspx/casestudies/en/emea/eu/fy2008_q3_id688?c=us&l=en&s=gen. Retrieved 27 June 2009. 
  13. ^ "OK Computer: EMA in Practice - article, The Environmentalist, Issue 77, 5 May 2009, Institute of Environmental Management and Assessment". http://www.iema.net. 
  14. ^ http://www.decc.gov.uk/en/content/cms/what_we_do/lc_uk/crc/crc.aspx

Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Power management — is a feature of some electrical appliances, especially copiers, computers and computer peripherals such as monitors and printers, that turns off the power or switches the system to a low power state when inactive. One power management standard… …   Wikipedia

  • Power Management —   [dt. »Energieverbrauchsverwaltung«], zusammenfassende Bezeichnung für Systemfunktionen, welche den Energieverbrauch eines elektronischen Geräts regeln. Da beim Betrieb eines Rechners meist immer nur ein kleiner Teil seiner Komponenten… …   Universal-Lexikon

  • Power Management IC — (PMIC) are integrated circuits for power management, these might be present on system on a chip devices. Models include the Freescale MC13783 and the Wolfson WM8350 …   Wikipedia

  • Power management keys — The power management keys are three keys on 108 key PC computer keyboards which control the computer s power management status. They are the Power key, the Sleep key, and the Wake key.The Power key is used both to power on and to power off the… …   Wikipedia

  • Power Management Unit — The Power Management Unit (PMU) is a microcontroller that governs power functions for Apple computers. This microchip has many similar components to your average computer, including firmware and software, memory, a CPU, input/output functions,… …   Wikipedia

  • Power Management — Energieverwaltung, engl. Power Management steht für: allgemeine Maßnahmen, um Energie zu sparen, siehe Energieeinsparung Maßnahmen der Verwaltung in der Energietechnik, siehe Energiemanagement Energiesparmodi von Computern nach dem ACPI Standard …   Deutsch Wikipedia

  • Advanced Power Management — (APM) ist ein Standard für Energiesparmethoden für Personal Computer, entwickelt von der Intel Corporation und Microsoft in den frühen 1990er Jahren. Heute unterstützt ihn praktisch jeder moderne PC (vor allem Notebooks, die besonders auf… …   Deutsch Wikipedia

  • PC-Power-Management — Unter PC Power Management versteht man jede Art von Mechanismus, der geeignet ist, um den Energieverbrauch von Computerarbeitsplätzen zu beeinflussen. In der Regel versetzt hierbei eine Software die Hardware in den unter den gegebenen Bedingungen …   Deutsch Wikipedia

  • Advanced Power Management — (APM) is an API developed by Intel and Microsoft which enables an operating system running an IBM compatible personal computer to work with the BIOS (part of the computer s firmware) to achieve power management.ACPI is intended as the successor… …   Wikipedia

  • Advanced Power Management — L Advanced Power Management ou APM (gestion étendue de l alimentation) est une interface de programmation (API) développée en collaboration par Intel et Microsoft. Celle ci permet au BIOS de gérer l alimentation du système, réduire la cadence du… …   Wikipédia en Français

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”