Why is my PC doing this?

[Sulaiman Chaabane]

So lately when I started playing games again there is a strange issue going on, So one-moment I'm at a good 140 fps but then in at 30? I'm not sure why it does this but I'm thinking because of a bottleneck, I'm ready to upgrade but I just need to be sure that what I'm doing is right.

Before anything my specs.

Aorus RX 580 8gb 

AMD FX 8350

Bio star TA970

Corsair Vengeance Pro 32 ram kit 

Heres a video of the FPS, At the top right you can see the FPS notice how at the beginning its 40, 100, 90, 130, etc. 

https://www.dropbox.com/s/re4jkp3imdtupt0/2019.07.03-14.43.mp4?dl=0

[Stormseeker9]

What are your temps like ?

[Sulaiman Chaabane]

Im not sure, How do I know?

[PopsicleHustler]

Your CPU is a bottleneck. FX8350 is very slow for modern games.

[suchamoneypit]

I would second the CPU bottleneck theory. Using a program like MSI afterburner you can monitor temperatures, and CPU/GPU usage. First make sure its not running super hot, next, you could have a chart for FPS and a chart for CPU usage, and if when your FPS drops, your CPU usage is going to 100%, then you have a CPU bottleneck and thats your issue.