I am facing Lag While Playing Gta 5 I have 4gb ram and 2gb nvidia 820m

Solution
That's probably because your GPU is way too weak for GTA 5. Even if you drop your settings to low and play on 1280x720 you will probably not get 30fps.
That's probably because your GPU is way too weak for GTA 5. Even if you drop your settings to low and play on 1280x720 you will probably not get 30fps.
 
Solution


This is not unexpected; the specs of your laptop are fairly anemic to run GTA V very well.