Moto G has a quad-core Snapdragon 400 CPU and 1GB of RAM. The Moto G is also quite lightweight thanks to its modestly-sized 4.5″ 1280×720 HD display, weighing in at just 143 grams. It originally shipped with Android 4.3 Jelly Bean, but has since been upgraded to Android 4.4 KitKat, and is promised future updates directly from Google.
Moto G is one of the few devices to get the instant Android 5.1 update from Moto. However if you want some change from the stock ROM, you can use the CM 12.1 custom ROM. This ROM will update the Moto G to Android 5.1 plus add more features and improve performance. Follow the guide below to install CM 12.1 ROM on the Moto G.