I'm somewhat annoyed with my New Dell Inspiron 13 2-in-1 5000 5378 w/ i7-7500u

So, I'm baffled by this issue and it actually makes me wonder why the heck a company would do this. So, this computer is lightning fast because of its: DDR4 2133 MHz memory, SSD, and i7-7500u with intel HD 620 graphics. I'm half-way happy with it and makes a great school computer for I can write on it and it currently has no problems running the processing software required for my EE major. But I have a big issue with its processor safety precautions.

Just making it clear..... I didn't buy this laptop to game. I bought it for school and wanted to lightly game away from home because the components are suitable to do so.... or so I thought.

So, I went to play overwatch on it because I saw that a dell xps 13 with the same specs (but the i3 kabylake) could do it smoothly and with decent graphics. As soon as I opened up the game I noticed that my cpu frequency dropped from 3.50 GHz to 1.65 GHz instantly and resulted in horrid performance.

I came to the conclusion that the cpu has a limiter so that it wouldn't get too hot, but then I remembered that the dell XPS is thinner than my computer and wondered how the heck it could run it but mine couldn't? I went to the service manuals for my computer and the dell XPS and I saw that the XPS has the same gimpy strand of copper leading to one dissipation fan as mine does, and I was left completely befuddled. I also have to mention that when I was running the game my computer never got hot (got warm but not even close to hot).

So, I pose this question for you all.... why can the xps run at maximum frequency under load but mine can't?

P.S. I also have to mention  that I'm disappointed in Dell for leaving so much space open inside of the computer. For the people who want to use their i7 to its full purpose need that extra space for another fan and more copper for heat dissipation.