I need some help mods admins anything please help

ok my computer is a quad core 6gb 1tb has like only 3 games on it and thats all and for some reason when im playing like any fps game like combat arms op7 or mw2 except like games that arent fullscreen like nittolegends or something like that the fps games dont lagg but after like 20 mins playing on a fps game it starts lagging worse then a singlecore and i know how bad a singlecore laggs i have a laptop singlecore so please help me i love playing my fps games please please help

ok if u havent done this, do it. first go to battery power plan and select "High Performance"
and then chek if tht works. if you alredy did tht.. read my PM thank me if i helped!