I use origin a lot, it is one of the only mods I think adds things to the game without completely changing it! After I installed Haema, my Minecraft had sudden lag spikes. I have never experienced them before.

Is anyone else having this problem, if so how do I solve it?

Great mod though, I love playing as the vampire! :D

Closing due to lack of information.

That's odd. How much RAM do you have allocated to Minecraft? If it's less than 1GB then the issue could be GC pauses.