Rendering with Movie Render Queue and Path Tracer

Hi! I am rendering with the Movie Render Queue and with Path Tracer, I am trying to render 240 frames, with nice quality (but not the best), and it its really really slow (at least 10 hours), taking in mind that it is a 8 seconds video (with 30 fps). That would be understandable if my GPU were working at 90/100% during the render, but during the process it works only at 20/30% of its capacity. Could be any way to use more capacity from the GPU to get fastest renders? Thanks in advance!