Originally Posted by BTViolence
It's an older game that's not optimized for newer hardware; there isn't really a better answer than that.
It's interesting because this is the only game I know that runs worse as hardware progresses, yet this isn't the case for a wide range of other previous titles.
Intel Core i9 9900K HT 5GHz
GIGABYTE Z390 Ultra
AMD ASUS STRIX OC VEGA 64
G-Skill Trident 2x8GB DDR4 4000MHz
Samsung EVO NVM.e 250GB
SeaSonic 1250W Gold
Corsair 900D + Custom Loop.