problem with games and hang.

Sir! i just Buy this phone recently from market. its 3Gb ram and 32Gb rom. but the game work so slow. not get slow. every thing is fine. even if i multitask so many application it won't hang. but when ever i open game it doesn't work smoothly. the game is not enough big like COC or Clashroyal. it lag but the graphic is so good.