So I have been playing on a MP modded server with me and 3 other friends for a while. I ussaly get around 110 FPS, however, now i get around 15, but that is only when looking at the central city. The area is filled with modded blocks. We tried replacing some of the modded blocks with regular MC blocks, but to no avail...it still lagged. We also tried removing the recent mods, but that did not work either. Also, chunks load in funky. They will load in some areas, but leavinh holes in other areas, also not happening anytime before.
A possibly unrelated problem is also that when joining the game, it loads in, but other players see that it says I left. I can still move around, but it takes about 1-2 minuets before I see a screen saying(see other attachment.) It also happens to other players.
We are at a loss here. Any help would be appreciated.