Once the game runs perfectly, copy the entire com.ea.games.nfscarbonrow folder to your PC or cloud storage. That way, if you factory reset your phone, you can just paste it back without redownloading the huge OBB file.
If your device struggles, enable Frame Skipping and set it to 1 . This artificially boosts performance at the cost of slight visual smoothness. Need For Speed Carbon Apk - Obb Android