Windows Phone 8.1 Multitasking Improvements!
Microsoft make huge improvements regarding Multitasking in Windows Phone 8.1
Here's what they'd shown during Build session:
Any device with 512 MB RAM running on Windows Phone 8.1 runs like a Lumia 920 (1 GB RAM Device) did on Windows Phone 8.0.
512 MB RAM would have 150 MB reserved for apps, while a device with 2 GB RAM would have 450 MB reserved. Now in 8.1, those strict memory caps are gone. They have been replaced with a system (Dynamic Memory Estimation) that watches how much memory an app is using and adjusts the memory cap. Phones with 512 MB RAM will show ‘resuming..’ sometimes, but phones with 1 GB RAM will no longer have that annoying loading screen. :)
Developers can enable an app to turn on in the background and load the pushed information before user even sees a toast, so when they tap on the message to open the app, everything will already found loaded No more loading screen...
When updating an app from the Store in 8.1, the phone will only download the data which has changed! So if 2 MB part is updates from an 50 MB app, only 2 MB will be downloaded as an update.
I think this will clear major annoyance, there is quite annoying to see 'loading' screen each time resuming to an app.