Disclaimer: please be patient with me and explain any suggestions, I'm not the most tech-savvy person out there so I apologize ahead of time.
My Alienware laptop is an Alienware 17 R2 and its a little over a year old. I used to be able to play games like Overwatch (which I will be using as the example going forward) at around 125+ frames a second on (I'm guessing High/Epic graphic settings), now its stuck at 60, when its at its best. More increasingly its frequently prone to dropping to around 40 frames, sometimes 30 and even around 20 at times. It's beyond frustrating and makes playing games almost impossible at times. My laptop runs at around 70 degrees Celsius when playing Overmatch if that helps at all.