Low FPS with a decent system

My system is a Ryzen 3700x, an RTX 2070 Super and 32GB of ram. I’m running the sim in 1440p and I have the graphics on high end with v sync off. I am having a hard time maintaining decent FPS, especially in bigger cities like LA and New York. I feel like I should be getting at least above 30 frames with my system, but I’m usually around 20-25. I’m not sure if it’s a problem with my system that I need to fix or not because it says that I’m being limited by my main thread, but when I check my CPU isn’t being maxed out. If anyone has any ideas I would really appreciate it.