I have 4 1x1 farms. Performance is degraded when plowing, planting and harvesting. After any of those steps the game runs fine, but when it comes time for any of those say goodbye to a playable game. Here is a screenshot that may help (I noticed this was what happened during all three of the above steps):
After all the crops were mostly planted (my farmers seemed to have forgotten five plots needing to be planted), I demoted all farmers back to workers, and made everybody cut down trees. Performance worked as usual with no issues. This was while the plants were growing, so that doesn’t seem to have any effect on performance as I see. Here is the finished work:
Anyhow, I’m done testing for now since performance makes this a lost cause. Thanks again for reading! I welcome continued discussion if there is any more to say.