I have a Lenovo ideapad y510p and it has a build in Intel hd 4300 and a Nvidia Geforce 755m. Some games like GTA IV or dota 2 i played very smoothly. But games like Crysis 3 causes a huge lag, and the settings of the texture is only " high ". I didnt even switch on the vsync. Then i went for some google searching then i found out some of them said that i using the intel graphic card to run the game so it causing lag, then how can i switch default graphic card to nvidia ?