Server sv_maxrate

Hello forum members.

I am hosting a server that runs DarkRP that is addon heavy. I will provide a link to workshop addon. I also run a couple of coderhire addons like Garrys logs and Arcbank. I am experiencing lag when my sever Hits about 30 players. Will little amount of props. I was wondering if I could have some help setting the settings like sv_maxrate. I have attempted it but I am unsure if they are correct or not.

sv_minrate 0
sv_maxrate 250000
decalfrequency 10
sv_maxupdaterate 66
sv_minupdaterate 10

The server Runs:

4 cores of a Xeon CPU clocked at 3.8GHz
4 gigs of RAM
Windows OS
50mbit Connection
Attempting to get 50 players on server.

WORKSHOP LINK: http://steamcommunity.com/sharedfiles/filedetails/?id=235992758

What tickrate is your server running at?

It is running at the default.

Half the tick rate to 33.

Is there anything I have to do with the other settings.

[editline]27th September 2014[/editline]

Done that and it still seems to lag