Issues with Inspiron 7577 - Audio crackling / glitches - Overheating - Frame drops

About two months ago I bought a 1300 euro Dell Inspiron 7577. The first couple of weeks it was working fine, but now there are multiple issues. Hopefully anyone here can tell me what to do about this. 

Frame drops

While playing any game I experience framedrops, where it randomly drops from 90+ fps to 15-20 fps for a 3-10 second periods.

Audio glitches / Crackling sound

When watching video's or playing games I can constantly here "crackling" audio. Every few seconds there is a "crackling pop" and sometimes a bit more than a pop. When im on Discord with friends they say that often the built in microphone drops out, and I feel like these moments coincide with the crackling audio. 

Also sometimes the audio glitches. It can combine with a drop in frames. It looks and sounds like the computer freezes for a couple of seconds, and then spurts out all the sounds that was supposed to be playing in those previous two seconds all at once. No idea how to describe it, a robotic scream would maybe be it. 

Overheating

The laptop gets very hot while playing any game (doesn't have to be a very high end game like the Witcher), especially the metal above the keyboard gets very hot. I can't touch it more than 4-5 seconds without it hurting my fingers. I installed Speedfan to monitor the temperature, and while playing a game it shoots up towards 70 degrees celcius. The laptop is only used on top of a table, with plenty of room around it, so the fans are not obstructed in any way. 

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I'd love to hear suggestions of what this might be. The laptop is clean, only a couple of games and a few small applications like Discord or VLC on it, that's it. It wasn't a cheap laptop to say the least, so I hope you guys can help me fix up this awesome laptop soon!