The Metro apps aren’t purely aesthetic. Some of the Metro apps features: Sleep, Hibernate. Kudos to Microsoft!
Microsoft has revealed another feature of the Metro apps in Windows 8: they can go to sleep
Just like a desktop or laptop, Metro apps can hibernate or sleep to save memory. This isn’t just down to users, either: they suspend themselves when not in use.
Apps that play music in the background or send and receive messages will be able to use multitasking APIs, though the majority of apps will just suspend. That means, like on iOS, you can have apps open in a frozen state and switch between them to resume from that point. The video is available to test now in the Windows 8 Consumer Preview, and appears to be almost instantaneous judging by Microsoft’s own system.
Memory will still be allocated to individual apps, but Microsoft has developed a system to reclaim memory from suspended apps (this is unlike iOS, which eventually closes apps if memory is low). If the OS or apps require memory, Windows 8 writes the working private set of an app to free up memory. This is similar to hibernation, which suspends Windows to avoid using power but doesn’t shut down the OS completely, resulting in faster boot up times.
Desktop apps in the past have always used RAM in the background, and wouldn’t suspend activity. This is known as paging, where data is stored to disk and retrieved if internal RAM is used up. The new system in Metro will avoid this.
Boot times differ
Microsoft says resume times for apps will vary, probably due to different sizes, if the hibernation technique is used. However, the company said it is working on ways to make the process as efficient as possible. Microsoft said that they expect many apps will take less than a second to resume.
It sounds like a great system if it works in practice, especially in Metro. For tablet-only devices particularly, users will likely open lots of apps and leave them open. That’ll happen across casual and ‘hardcore’ users, because people use apps out of curiosity to check the weather or when a sports game is happening. iOS devices handle lots of apps and, with faster chips and more RAM, rarely slow down to where it is noticeable.