Effecting FPS like crazy on Heavily Modded Server

[n0itLT]

It seems when I run this mod it causes massive lag on our world. Even in single-player, it causes massive lag; however, without it no lag.

[Cadiboo]

Please clarify what you mean by lag. Do you just mean low FPS or do you also mean game lag (e.g. lag when breaking blocks or hitting entities)?
How many people are on your server?
How many entities are on your server?
Does disabling collisions in the server config fix the issue?

[n0itLT]

I will do more testing, It seems to be fine without the mod; however, when I add the mod my fps (frames) drop like crazy. I believe my server runs fine. Could try again

[Cadiboo]

What exact version of the mod are you using? Does disabling collisions fix the issue?