Jean_40 :
Sorry I accidentally press the arrow.
Fix'd.
You may think that GTA V is a "heavier" game, but in truth Mirror's Edge: Catalyst is very CPU and GPU intensive. If your fan is firing up when playing Catalyst, it's because your computer is having to work harder to run the game.
One option would be to buy a cooling pad for your laptop. I personally picked up one with 3 fans back when I started really gaming on my old laptop; prior to getting that, World of Tanks would actually BSOD the poor laptop due to overheating after about an hour or two of play.