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Clay Nichols
Asked: 2009-10-18 22:14:39 +0800 CST

How much power does Windows 7 realistically (typically) save?

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I've read that Windows 7 has some power saving features and have even heard claims of a 1 year Return on Investment in power savings.

However, all I found was reference to saving .5W by disabling the network adapter if it's disconnected, and reducing power to audio devices (if none are in use). I can't see this latter one having much effect since the bulk of my audio power is the external speakers and even if they are off, the transformer would be consuming power (I think) and certainly consuming power if on even at the lowest volume setting. (I.e., to save significant power on the audio you'd have to physically turn off the speakers and maybe unplug them.

Is it MicroHype? If not, how much power can Win 7 save on a desktop PC?

windows-7

2 Answers

  1. Best Answer

    While Windows 7 has measurable improvements on battery life for many perhaps most laptops by:

    • powering down peripherals not being used
    • reducing clock cycles of the processor when possible
    • more agressive use of processor sleep
    • synchronizing interrupts so as to further reduce power consumption
    • enabling better video power management
    • adaptive video brightness
    • turning off processor cores that are not needed
    • using the slumber feature of SATA hard drives
    • turning on services only "on demand"
    • more efficient use of hard disk reads
    • slowing the system timer from 1 ms to 15 ms

    Only some of these improvements would apply to today's desktops. However, as enterprises and individuals care more about power consumption in general, I would imagine that manufacturers will provide similar power savings features in desktop computers as well.

    This infoWorld article shows a measured 17% reduction in power consumption on a desktop from XP or Vista to Windows 7 which is pretty significant.

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  2. There have been a number of studies that compare the power consumption of differing web browsers, and that's on the same hardware. If you expand the ideas that cause one browser to consume less power than another to the whole operating system, then it would be possible to make those sort savings.

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