That's kinda hard to determine since you didn't provide any specs of your pc nor your settings in-game or out side of the game (like power options, DSR etc..)

What could help is to check if your pc is in on power saving mode, bump it up to at least balanced. Update graphics driver, put everything on low inside the game. Bump everything up a notch play a bit, then repeat till the game starts to lag. Other then that, idk. Game does have some performance issues even on high end pc if you've built alot of things. There is also a thing where the game auto-saves every like 10 minutes and it drops fps