Whats is Fast Dormancy? For full details and explanation about it, visit this link. Keeping fast dormancy disabled can increase battery life of your device. I have tested this on three devices i,e Samsung Galaxy S3 i9300, Samsung Galaxy Note N7000 and Galaxy Note II N7100. Here’s how you can do it too.
Disable Fast dormancy on Galaxy Note N700
It is very easy to disable it on note N7000. Simply dial *#9900# from your phone and tap on Enable fast dormancy.
I have tested this on Note N7000 running Android version 4.0.4. I am not sure if it will work on Android 4.1 (jelly bean) or not.
Disable fast dormancy on Galaxy S3 and Note II:
You will need to root either devices to disable fast dormancy. You can explore Xda forum on how to root your phone. After rooting, download FastDormancy Toogle from Play Store and then a tap of a button will do the trick for you.
The developer of this app states that he has only tested this on Galaxy S3. But you can use this app note Note II as well. I have tested it and it works like a charm.