Server performance

Hello, i’m making an online fps and after some optimizations i still can’t make it run like i would.
Characters are often lagging, there is a lot of rubberbanding, and after some time the performance decreases making everything lag a lot.

However i noticed that while lagging the ping is very low and the only pc which can run the server quite good is one with an i7 even if lag is still present. The lag is already visible with two players connected and gets a lot worse with more than 5.

What could i do in order to improve the performance a bit?
Currently i’m using these values in my Character Movement (Networking) tab, should i tweak them?

107874-character+movement+values.jpg

Thank you for your help.