I play with some friends and I´m not the host and every day when the npcs meet at the town centre of pumpkin ville my game has only 1-2 fps. Then the only thing I can do is leaving the town and go to my river farm plot. There I can play but lag spikes come sometimes too.
I often have a completely black screen after sleeping on my multiplayer server. I can still see my mouse cursor and hear the game, but I'm left to exit to the main menu and reconnect. The other player doesn't have the problem when it occurs to me.