Insane lag on Pixelmon

Can someone please figure out what’s happening with my server, I own a pixelmon server with 20 active players. For some reason, with 6 players online, I was getting 10 Mbps up, around 2mbps per player. My CPU was pinned at 100%. The render distance is 4.
What do I do? Please help, many people depend on this as their source of entertainment.

Start by adding Aikar’s flags. Click on “FIX THIS” in your report, next to “Wrong Garbage Collector”.