Aspire VX5-591G0 - freezes/stuttering

Hey, first my specs:
GTX 1050 4GB
1TB HDD
i5-7300HQ
8GB RAM
Windows 10

BIOS 1.05

So I have the laptop for almost 2 months now, and it performs really well when it comes to Internet browsing/yt/movies. However, games tend to work terribly sometimes. The only game which works fine is The Witcher 3, others like: GTA 5, Far Cry 3, Hitman Absolution or even Resident Evil 6 are more or less problematic. GTA 5 works well for about 5-10 minutes, after that the game either stutters every 10-15 seconds or sometimes freezes for 1-3 seconds (the longer I try to play the worse it gets). Far Cry 3 works pretty well but as soon as I get into a car and start driving through the map the fps drops from time to time( or I don't use the car, and it starts to stutter after some time anyway). The only clue I obtained is from Hitman Absolution, where the freezing occurs in the exact same spots on the map (once, after reloading the game), and also randomly after 10-20 minutes. 

The things I ruled out:
- thermals are fine (CPU can hit up to 80C, GPU never goes beyond 72)
- I disabled sound devices (Latency tests showed it may be caused by the audio driver)
- Changing the Page File size
- Installing the game on a much better external HDD (USB 3.0, performance is much better compare to an internal one - no improvement whatsoever (except for much faster loading times))
- Drivers are up to date (checked couple of Nvidia's older drivers - no difference)
- System is clean, the only antivirus currently installed is Windows Defender
- I tried changing Nvidia settings - no difference, though I can't force V-sync, only the in-game one works
- In-game settings do not matter - the same stuttering/freezes
- Power options - whether the laptop is on battery or plugged in - the same issue, everything is set to the max performance

I haven't had a single Bluescreen nor any crashes of the games mentioned above
Any ideas what may be the cause?