There have been a number of requests for a place to discuss the performance and FPS issues in the current game version. Consider this that place!
A thread posted a few days ago suggests a possible reason for the issues, but is as yet unconfirmed.
Please feel free to share your experiences with game performance in the latest update here.
We'll be removing duplicate posts about the issue in favour of this megathread.
submitted by /u/samwalton9