When I am harvesting food (Wheat, carrots, potatoes, etc) from my 8x8 plot, the games frames per second (FPS) goes from 60 down to 9. 

1. Launch seed
2. Create 8x8 plot of dirt with tool
3. Plant seeds for wheat
4. Wait until all are full grown
5. Using an axe, cut down all the wheat without trying to collect it
6. Watch FPS drop with all the instances of wheat and seeds on the screen

Attached is a screenshot of the plot and tool showing FPS off to right.