There was another post on here about fps loss but got locked,    the same thing is happening to my server too mine was dropping to between 8 - 45 and I tested it with only 1 base spawning and no ai, fps starts high then just drops massivly 

I thought it migth have been a host issue, but it's doing the same with gtx and low.ms - once you remove the plugin and restart fps is back to normal.

When I was asking for help from low.ms he informed me " It seems as soon as players start joining the FPS on the server takes a real big hit. "