[SOLVED] Lower fps the more i play

[gerardost]

So heres the thing, i play pubg and the 1st minute i get around 160 fps average on the training grounds, after 2 mins i get around 130, after 5 mins i get 90, 70 and so on while time passes by.
I don't know whats happening, i bought a rtx 2070 super and first week i had no problems with fps, after that games started to decrease fps the longer i play them. I don't know if my PSU might be the problem because its old and sometimes makes buzzing noises when playing games. I know my CPU can bottleneck but the first week i was playing i didn't see fps drops at all.
Link to FPS , GPU and CPU usage and temps here:

1st min of gameplay: https://ibb.co/3R1vPxg
after 5 mins of gameplay: https://ibb.co/tQ4NX2d

If i close the game and re open it, i get to start again with around 160 fps again, then it starts to decrease after a few minutes. According to the image, there is no CPU or GPU overheating so what could be the problem??
Running PUBG on ULTRA 1080p

Specs:
GPU: 2070 super Gigabyte
CPU: ryzen 5 1600
RAM: 16gb Corsair Vengeance 3000mhz
MOBO: gigabyte ab 350
PSU: Corsair cx750m (4 years old)

 

[mdd1963]

Assuming temps are no issue (monitor core temps w/ RyzenMaster?), perhaps your BIOS is attempting to enforce the normal 65W TDP limit, with associated 'x amount of seconds at peak clock speed' sorts of rules, and then downclocking....? (I'd expect those symptoms to manifest themselves running even a CPU-Z/bench/stress CPU session 20 minutes long if that was the issue)

Search your BIOS for performance options (enabled), and disable any possible 65W TDP/power limits, if present...

Normally WIndows power plan at Balanced mode is more than sufficient, as my system (although not Ryzen) holds peak turbo/boost speeds all day long under an all core load, but, down-clocks to 800-1000 MHz almost instantly when just loafing around at the desktop, forums, etc... You can try performance mode if necessary to see if that helps...