Server laggs when spawning NPCs/Players join/Shooting

Hey,

I’ve setup’d an GMOD Server with DarkRP.
So, everytime a Player joins the server, the server times out for a little time.
This also occurs when you are shooting 10+ Bullets or spawn NPCs (even at one)

My Addons are:

My Server Details:

Start Script:
screen -S darkrp ./srcds_run -game garrysmod -port 27015 +maxplayers 50 +map gm_flatgrass +host_workshop_collection XXXXXXXXXXXXX -authkey XXXXXXXXXXX +gamemode darkrp