I am running the demo version of Invigorator pro on a fairly top end i7 machine but i find the response sluggish in the fx window. Would this be because the .obj file I imported has too many polygons or does the demo version work a little slower?
The demo version should not make your project run slower than the retail version.
The reason for slowdown would possibly be because the object is really large, and maybe really complex as well. In this case, you may want to turn the resolution of After Effects to Half, and turn the 3D Invigorator layer to Draft. Also, be sure to leave the Draft Object Faceting value as "3.0" or higher.