from DJI's forum:
IMPORTANT ! HERE IS HOW TO EASYLY FIX THIS ISSUE !
1: Reset you tablet to factory default, after is is updated with lastest Lolipop Firmware.
2: Install Zapper Task Killer
3: Select all selectable processes using Zapper, and Kill All.
4: Install DJI Pilot From Dji Download section on the website(Make sure you allow installation of softwares from unknown sources).
5: Go in Apps option and manually select all apps, and disable notifications for every single app you can do so.
6: Go in App Store and disable automatic updating of all apps, by clicking the 3 dots on the top corner.
7: Go in developer options of your tablet and set “Logger buffer sizes” to 256K(Not sure if it's important but seams to have helped for me).
8: Reopen Zapper again and Kill all processes again
9: Kill all processes again using Zapper(Yes why not twice !)
10: Open Dji Pilot and login to your account
11: Plug your remote, and then turn it on
12: Turn on you Phantom 3
14: Enjoy Lag Free flights…
I was having constant Lags every 3 seconds, on my Nexus 7 2013, did this in this order, and now i'm lag free, tested full 20 min flight.
Also i advise you set ALL animation options in the Developer options to OFF ! To increase performance even better…