How to reduce Lag or Ping in unity networking

Hello guys, i have a multiplayer game that works fine, with no lag, ping goes about 5~20( IF the server and the client are close ). Then, i have a server running far away from the clients, and the syncronization of the positions, etc is very bad.. ping goes around 200~300.. Any ideas of how can i fix it? The actual sendrate i'm using is 50.
Thanks!

Edit: When i remove the enemies, everything goes fine.. so the problem is that there is too many enemies on the scene? can someone give a hand ?