1. Computer Power Consumption Created By Paul Briskey February 18, 2008

2. Outline Computer Power States Computer Power Consumption Factors Notes On Energy Star Power Test – System Configuration Power Test Results Conservation Steps and Software Notes Changing Power Management Settings Sources

3. Computer Power States Power StateDescription S0 (At Desktop)Normal working state (either idle or active). Computer is ready to go. S3 (Sleeping)Monitor, HDD, and other peripherals are turned off but RAM is still on and holding data. Fastest to wake up. S4 (Hibernating)All data in RAM is stored to the HDD and everything is shut down. Medium amount of time to wake up. S5 (Power Off/Mechanical Off)Computer is off but still plugged in. Must go through full boot process. G3 (Power disconnected)Power strip is off or computer is not plugged in. Must go through full boot process.

4. Computer Power Consumption Factors Everything makes a difference – Power consumption is based on voltage levels and current requirements. These will vary drastically not only with component attributes (i.e., processor speed), but also between brands. – Power management options in the operating system as well as in the motherboard BIOS also change consumption. Performance often precludes power savings – Increases in speed result in more power use. For example, an increase in memory speed causes it to become unstable so the memory voltage is increased. This directly results in more power use.

5. Notes On Energy Star For Computers/Motherboards Energy Star is a product certification that manufacturers can apply for. Each product type (desktop, server, etc.) has several categories, each with different qualifications. Compliance is taken very seriously since ONE failed test at any time prohibits certification for the failed product indefinitely. Test conditions are specified by the manufacturer. Therefore, an E-Star compliant system might only pass when specific parts are used and many system options are disabled.

6. Power Test – System Configuration Gaming SystemMultimedia SystemEnergy Star Board BoardIntel D975XBX2NVIDIA nForce660 ProcessorIntel Core2 Extreme (45nm, 1.165V) Intel Pentium Extreme (65nm, 1.525V) Multi-core RAM2GB PC2-5300 (1.8V)4GB PC2-6400 (2.2V)>2GB HDD500GB SATA II 200GB SATA II 300GB SATA II 500GB SATA II 240GB IDE 120GB IDE >2 HDD Graphics CardGeForce 8800GTS-512GeForce 7900GTX-512>128MB dedicated Sound CardX-FI Xtreme Music None OtherTV Tuner Card, PCI USB Card, 4- 120mm and 1- 140mm case fans, DVD ROM (IDE), DVD-RW (IDE) TV Tuner Card, 2- 120mm case fans, Wireless-G Network Card, 13in1 Card Reader TV Tuner/Video Capture Card Note: Parts list is not exhaustive. Energy Star configuration for Class C desktop board

7. Power Test Results Power StateGaming SystemMultimedia SystemE-Star Board* S0 (Active)**250W300W- S0 (Idle)163W212W<95W S3 (Sleep)7W6W<4W S5 (Off)6W5W<2W kWh/ month Cost/month @ $.10/kWh kWh/ month Cost/month @ $.10/kWh kWh/ month Cost/month @ $.10/kWh S0 (Idle) 117.36$11.74152.64$15.26<68.4<$6.84 S3 (Sleep) 5.04$.504.32$.43<2.88<$.29 S5 (Off) 4.32$.433.6$.36<1.44<$.14 *E-Star board power requirements are based on the Intel Desktop Class C standard (classes A and B have more stringent power requirements). **Active Test: Running 3DMark06

8. Conservation Steps & Software Notes To Conserve Energy: Turn your computer off at night. (Basic) Change power management options on your computer. (Intermediate) Disable unnecessary motherboard options. (Advanced) Disable unused hardware in the device manager or set it to enter low power mode when not used. (Advanced) Using Software: You can download software to change power management options for you. Many systems already include this. If you can do it yourself (it is very straight forward) you will avoid another program running in the background slowing your computer down. This software is not capable of changing any motherboard options in BIOS

9. Changing Power Management Settings 3.Select a power scheme and hit OK 1.Right click on the desktop and select “Properties” 2.Select the “Screen Saver” tab and click “Power…”  Explore this dialogue to find other options for power saving

10. Sources Bolioni, Thomas, et al. “Energy Star* System Implementation.” April 2007. Intel Corporation. 18 February, 2008.