[TheOriginal1337]

Indeed, could be something with your host. Or there is something in the code that makes your server lag. I used to have a problem with playerstats saving. There was a timer in my script saving every second all files of players. So when there were 50 players it started lagging because it had to save all the 50 files every second.

But try to check your script and make sure there is nothing like a timer running something every second as I had.