Extreme, consistent FPS drops

Hello internet,

In the past few months I realized something was wrong with my gameplay. Which then was noticed that a lot of graphic intense games such as Rainbow six siege, Arma III, player unkown battleground and a lot more, have freezes (FPS drops).

I have tried a lot of things such as installing the MSI gaming app, updating drivers, checking faulty RAM, decreasing space on my hard drive, running malware and antivirus scans, looked up tutorials online on how to get the best optimisation for nvidia control panel and reinstalled my graphic drivers using DDU and installing them manually.


I'm tired and want to get to the bottom of this. If it includes any upgrades then so be it. I just want all my games playable.

Thank you guys so much in advance!

Specs:
Motherboard - MSI 970 gaming
GPU - Nvidia GTX 970 4GB
Operating system - Windows 7 professional
PSU - EVGA 750 W gold ATX Modular with active PFC
Ram - DDR3 ( not sure about the rest)
CPU - AMD FX8320
CPU and GPU approximately around 45-60 when playing games.


Here are my settings for Nvidia control panel:

Ambient Occlusion: Off
Anisotropic filtering: Application-controlled
Antialiasing - FXAA: Off
Antialiasing - Gamma correction: On
Antialiasing - Mode: Application-controlled
Antialiasing - Setting: Application-controlled
Antialiasing - Transparency: Off
CUDA - GPUs: All (Select all available options)
DSR - Factors: Off
DSR - Smoothness: Off
Maximum pre-rendered frames: 1
Multi-Frame Sampled AA (MFAA): Off
Multi-display/mixed-GPU acceleration: Compatibility performance mode
Power management mode: Prefer maximum perforamnce
Preferred refresh rate: Highest available
Shader Cache: On
Texture filtering - Anisotropic sample optimization: On
Texture filtering - Negative LOD bias: Allow
Texture filtering - Quality: High perforamnce
Texture filtering - Trilinear optimization: On
Threaded optimization: Auto
Triple buffering: Off
Vertical Sync: Off
Virtual Reality pre-rendered frames: 1


I use a program called 'Custom Resolution Utility' for a custom resolution for my computer (1920 x 1080) if that causes anything. https://www.monitortests.com/forum/Thread-Custom-Resolu
I use this because the resolution is stuck on a low resolution with 'Generic non pnp'. Therefore this program helps. I also use two screens and I use a HDMI to see if it fixed the issue however hasnt.
My monitor however still states 'Generic Non-PnP Monitor (1920x1080@60Hz)' which could be the issue?