Server lagging when people walk?

So when you walk on my server it lags. How do I fix this?

Don’t walk.

[sp]Get a better server PC[/sp]

Get a new server

That’s a hardware issue.
I recommend renting a server from a hosting service if you lag when walking.

Post specs just in case.

I’m renting from Xenon servers, but the problem seemed to stop a while ago.