Lag issues from a Dell Inspiron 15z Ultrabook, core i5, 6GB RAM

I am having lag problems while trying to play a game. While the game is being played, task manager says my processor is running at about 25% and my RAM is only 35% used. Why would I be having issues with game play when my buddy is sitting right beside me with a far inferior PC and having absolutely no issues? I just finished a malware clean up with the help of the guys over in the Virus and Malware forum. It seems to be all clean... I am at a loss.

It's related to your graphic card, not to your computer You should check your drivers, update your computer and keep it clean.