Optimize Unturned Server

Hey guys, im hosting about 3 server Unturned, when my player reach about 40 in one server it will cause lag and stun both players and zombies. Meanwhile, my server resource still good (CPU: 40% and RAM 70%)

Anyone have the answer, please help me. Thanks

Sorry for my bad english. Hope you still understand my question.

Right click the cpu picture and change the view to lochical . You will see that one of your proc uses up all.
Unturned on MS Windows can only use 1 !

maybe you are right, i increase from 2Ghz per cpu to 3Ghz and it help me a little bit. But Unturned on Windows only use cpu 1 is wrong, because all of my cpus run in same usage.

Thank for helping me

Servers use only one thread. That one core is probably dying.