Extreamly slow while handling large data

I would like to ask if anyone is facing this issue where it is extremely slow to open / view / edit / save large text files (json, sql, csv, with 1GB and above in size). I have tried opening a 2GB JSON file and it takes nearly 4 hours to completely open the entire file but once the file is finally open, it crashes.

FYI I am using Sublime Text 3 version 3103 but this problem has been here since Sublime Text 2