Rule out the obvious first
81 of 1,119 written reviews (7.2%)
Is it your settings?
Do this before anything else, because several reviewers report that lowering settings fixed it, and several report that the same settings are fine. Turning settings down a notch is the cheapest test available and the fastest way to tell an optimisation problem from a machine problem.
Limit: Self-reported, and lower settings also mean lower resolution on some setups. Without a resolution-scale control, the two are not separable.
“fps consistently even with all the graphics settings turned down. It's a shame, feels like it would be fun otherwise, hopefully they patch it to improve things.”