@Murat Türe Memory leaks are definitely the issue. Your latest patch has improved things, but it's still not fully fixed. I can run the game for around 10 minutes before i am forced to restart it due to a sudden loss in frames. Most of my settings are on very high, not including shadows and particles, which are on medium. These are my specs:
GPU: NVIDIA GeForce GTX 1050 Ti
CPU: Intel(R) Core(TM) i5-7400 CPU @ 3.00Ghz 3.00Ghz
RAM: 8gb
System type: 64bit Operating system, x64-based processor
2 drives, D and C. Game installed on D (Like all of my games).
C drive (mainly used for PC essential) has 21.8GB free out of 110GB
D drive has 260GB free out of 931GB
I also have turned V-Sync off (Cause someone suggested that) and have set the frame limiter to 60fps, which is my pc's refresh rate.