Gaming Notebooks

Recently I bought HP Pavilion Gaming (i7 8750h @ 2.2GHz, 12GB RAM, 120gb SSD + 1TB HDD, GTX1050Ti 4gb) and I have problems while trying to run intensive application, including games (tested GTA V and Battlefield 1) and softwares (AutoCAD...).

Note: I've updated all drivers + installed latest BIOS for my product.

I've downloaded Afterburner + RivaTuner and used them for monitoring of CPU and GPU core speeds and temps. 

My BIOS is locked so I don't have any additional options to configure rather just to leave it as it is.

About games and softwares. My CPU when is on charger (Power Management is on High Performance) does not run on its core speed (power management is setup correctly when charging, cpu is at 100%). Problem is it goes to 800MHz everytime, no matter if I'm on battery or charger. While idling on desktop, if i run CPU-Z, it shows random core speeds that jumps from like 800 up to 4000 or so. I understand that's turbo and that CPUs are optimized to work on lowest speed and when you run certian intensive app, it boost up. But in my case, its opposite. As soon as you launch game/software, CPU speed lowers to 800MHz.

Let me talk about games first.

GTA V:

As soon as I start game GTA V, I can see CPU works on normal speed 2.2GHz or even higher if turbo activates. And when you click in main menu "Story Mode" it loads up and spawns you inside world. While loading game, it says on screen CPU works on random speeds 2.2GHz and more. But, as soon as it loads the game world (example you spawn inside house) it lowers CPU core speed to 0.8GHz and it sits there. FPS is somewhere around 30-45 MAX. It's just not smooth. Even when driving around, shooting, trying to load most of game textures, same thing happens. Temperature is normal, somewhere around 50-60 Cels, but core speed sits at 800MHz. Then after some time I decide to quit, and as soon as i Exit game, those monitoring numbers reset and they jump from 800 to 2200 and game exits to Desktop.

Battlefield 1:

Pretty much same as GTA V, only difference is that FPS is way lower, somewhere 15 to 30 FPS max. It starts game with decent core speed, and as soon as it loads into game world, it drops to 800MHz. GPU/CPU are not getting overheated or something like that. I assume problem is in CPU because it looks that CPU is "bottlenecking".

As for Autocad, it got some rendering issues when trying to draw, everything just looks kinda...sluggish. It doesn't feel smooth at all. I expected more from this machine, considering it's price.. 

Hopefully there is someone who can help me out with this or give me advice. It's kinda sad that you have decently fast GPU inside machine and you can't use it's potential.

Thank you for answers!

EDIT: Can someone tell me what is exact AC Adapter that comes with this laptop? Voltage etc.? I think they might switched and gave me wrong one so maybe that's the cause of this? My current AC adapter is 65w and on website it says 150w...