5 Ways Windows 8 will help apps cut power consumption | ITBusiness.ca.  (No longer available online. Original text included below.)

Windows 8 is coming soon, and much thought has gone into optimizing it to run well not just on desktops and laptops, but also on tablets and even smartphones. Part of making an operating system friendly for mobile devices is making it power conscious, able to do everything you want while using as little power as possible. Here are some of the ways Windows 8 has been optimized so your apps use less power, so you can get more work done.

Travelers Ritual

If you’ve ever taken your laptop on a long flight hoping to get some work done, then you’ve probably gone through a “travelers ritual”. To extend your battery life, you shut down all unneeded apps, and disable all the services running in your task or menu bar. In our experience doing this can often extend your run time by 25%.

When you travel all day with your phone, you generally don’t need to do this. Phones, and tablets as well, have been designed with a closer eye to energy efficiency. Background apps are less likely to have an impact on your battery. Windows 8 will take a similar approach: if you can’t see the app, then it shouldn’t use power.

Improvements

Desktop apps that you’re currently running at work will still run as they always have, and besides some minor benefits due to operating system improvements, will use as much power as they have in the past. The Building Windows 8 blog details how Metro style apps written for Windows 8, however, will have options to reduce their power footprint, extending your battery life. 

Background Friendly: Metro style apps will be suspended when moved to the background, with the Windows Scheduler no longer giving them CPU cycles. The app is ready to work instantly when pulled to the foreground, but until then sits idle, using no power.

Background Actions: There are some tasks that still need to happen, even while an app is in the background. Microsoft has accommodated this by defining key scenarios that are supported in the background for Metro style apps:

• Playing music
• Downloading a file from or uploading it to a website
• Keeping live tiles alive with fresh content
• Printing
• Receiving a VoIP call
• Receiving an instant message
• Receiving an email
• Sharing content
• Synchronizing content with a tethered device

Windows 8 includes APIs that allow Metro style apps to complete these actions in the background in a way that is power efficient. 

Connected Standby: Phones and tablets rarely get turned off, they generally sit in a “standby” mode, using little power. Windows 8 accommodates this functionality by supporting a “Connected Standby” state in new hardware that supports it. A “Desktop Activity Moderator” will enable apps that otherwise only understand awake and sleep modes to work in connected standby mode. The moderator will allow select processes to run, while preventing unnecessary background tasks from draining your battery. 

Metro Envy

Windows 8 is making a dramatic transformation from a desktop operating system to a mobile device operating system. With over 75% of the PCs currently sold being battery powered, the emphasis on power efficiency is well placed. One thing that is apparent in seeing these new power saving techniques is that much of the software your business currently uses will need to be rewritten to take advantage of these improvements. Running power hungry desktop apps on a Windows 8 mobile device will make us quickly desire a Metro style version to extend our devices run time, and increase the amount of work we can get done.