I'm writing a custom obj model loader/renderer, not using the existing one because i want to load models dynamically, bypassing ResourceLocation thing + just want to do it myself.

I'm using simple minecraft Tessellator to render a whole 3d object and as a result i'm getting a massive fps drop rendering high poly models. How can i fix that ?

 

Make sure that you are not re-initialising the tesselator for every triangle drawn, you can init it at the start of the whole draw process and close it at the end for better performance

Nope, that's not the case