Laptop used to run games smoothly, now lags intensely in 5 minutes in game?

[Endeavor]

Okay so I used to run Batman arkham origins, Battlefield 4, and all those big games perfectly fine.
My computer can runs these games on High. About a few months ago, when I play just about ANY 3d game really, the laptop will make a static-y, popping like noise from the speakers and lag when I'm in-game in about a few minutes and the voices in-game sometimes distort and slow down a little. I bought a new cooling pad, scanned for viruses with Windows security essentials, and scanned for mal ware with Malwarebytes Anti malware. The malware would often say I had some "PUP" files going around, and quarantines them. WIndows SE doesn't ever say anything about any viruses. So if its not overheating, because of a new cooling pad, and not any malware or viruses.. what could it be?

 

[Endeavor]

My processor is a Intel(R) Core(TM) i7-4700MQ CPU @ 2.40GHz (8 CPUs), ~2.4GHz
and my video card is a NVIDIA GeForce GTX 765M

 

[Hendlton]

Well, that does sound like the CPU is heavily thermal throttling. Open the game in windowed mode, if it still lags, check the temperatures and the clock speed of the CPU while the game is lagging. The cooling pad might not be doing anything if the laptop's fan(s) is(are) dusty, I recently went from 96 C (not kidding) at idle to around 70 C at full load just by cleaning the fan with some canned air. (If you do use canned air or an air compressor, make sure that the fan can't spin because you can damage it that way.)

 

[velo3100]

Sounds like a busted fan to me. Have you opened it up to check if it is broken?