I managed to almost kill my family and friends minecraft server over the weekend, it was just so slow.. Blocks were really laggy, and I could walk twice as fast as the minecart would go.
I set all my settings to basic, rebooted my computer, rebooted the server, built a new server and put the world on that, it was still the same, when I logged in the Java/Minecraft process went to 98.7% CPU utilization.
Lizzie logged in and said it was fine for her. I went for a walk to another part of the map and found it was much better after a while.
I went back to our first village and it slowed again.
I was a victim of my own success!
While building and testing an automatic fishing farm, I left minecraft logged in running all night. I was still in range of the first village’s automatic chicken farm, where all the eggs are collected and fired back out to spawn more chickens. I had to painstakingly walk there getting slower and slower as I approached and slaughter over 800 chickens. I was literally at 1fps at the start, and finished back on a more reasonable 12-15 fps.