I will tell you easily install android 5.0 Lollipop,so many android 4.2.2. jellybean device is running slow,then I will tell you solution is upgrade Lollipop 5.0,5.1,5.1.1.
First, go to play store on your mobile and search for EFS "IMEI" Backup and install the EFS backup.It is used for any wrong upgrading 5.0 Lollipop it will backup 4.4 jellybean software.Connect your mobile device to your computer using USB cable.After connecting your device file is shows the internal and external memory on your PC.
Open the ESF backup folder makes an option and mark the external card for backup your 4.4 jellybean software and save EFS (IMEI) backup after completing your backup copy your backup memory into computer hard disk and copy the data to computer folder which folder you want to backup the file and paste the file on your computer.
Copy the CM12 and apps file to your mobile device external memory card.Before going for that you need to root your phone.After root, you can remove your sim cards and switch on the phone while removing your sim cards.Click down volume button,power button and menu button at a time.
Every device shows your entire ROM and clicks on ODIN 3 to extract the file and install file to run your PC connected with USB cable to your phone click the "up volume" button to on ODIN software.
Click PDA file and custom ROM file and start ODIN 5.1 Lollipop open the app and click on cwm recovery non-touch and click open you can successfully install 5.1 Lollipop.Press volume button,switch on button and menu button.you can perform three tips 1. Wipe data factory resets 2.Wipe cases position 3.Advance wipe Dalvik cases
First, click on the first option and it will take few seconds and do the same thing to another two.After downloading 5.1 Lollipop and it will show you go back option click on that option and reboot your device.After rebooting your device you can feel flashing logo and after four to five minutes to setup click next and select your wifi connection and give instruction to complete it.Finally you get smooth and fast Android Lollipop 5.1.