I assume this is a laptop with optimus....

The game will use The Intel HD 4000 for 2d and your Nvidia gpu for 3d (unless you tell it not to).

As far as Turing off the HD4000 and just using the nvidia gpu... The nvidia gpu doesn't have any display port The Nvidia card passes the video back and forth between it and the Intel HD 4000 with does the display composition and actual output.


Fyi its not lag...

Its called low fps...

Lag would be a connection issue.