Does the background render script not use the GPU for rendering 3d created inside of AE? Normally every render I do is with the background render script to image sequences, then it goes into AME if I'm rendering out video for a server or into Vegas if I'm going to mix. With my z620 with dual 6core Xeon's I can usually get 10 different renders going of the same comp if it isn't GPU or too CPU intensive.