Question FPS drops rust

Oct 4, 2020
Hello there.
I've been struggling for 6months now. I am playing Rust and after 1 hour I get a fps drop from 60-100fps to 50-65fps. I can't find what my problem is or fix it. When I restart the pc the fps is good again. I only have this in Rust. I had the following problems but its fixed:
-High temps
-Dirty pc
-Thermal paste was old
My other problems what I still have and don't really know how to solve:
-Gpu usage is okay but it decreases a little over time
-memory usage increases over time
My specs:
-Gtx 1060 3gb
-i5 7400
-2x8gb ddr4
-Micro Atx motherboard
-ssd 256gb
-hdd 1tb
-PSU: Liteon, PS-7501-5, 500W
My temps:
While gaming:
Cpu: 40-60 degrees
Gpu: 60-71degrees.
After the fps drop the gpu: 59-64 degrees.
cpu: 60-90%
Gpu: 45-60% after fps drop gpu: 35-45%
My memory usage was all the way to 80% today its so weird.
I think thats my problem, but I am already using memory optimizer(s).
I am so happy when this stuff is fixed. I've tried a lot of things but not a lot changed. I can't say what I've tried because its to much.