Just to make my question more clear:
I'm wondering why all my CPU cores are not being used. The fact that CPU usage is less than 50% is making me think that the Rendering process could be MUCH faster if I could somehow get the full potential power out of the cores.
am I wrong?
Sometimes, CPU processing is not the bottleneck.
5 hours is not at all an unusual amount of rendering time for 10 minutes of video when using heavy effects, 3D, etc.
See this page for resources about making Adobe Premiere Pro and After Effects work faster: http://adobe.ly/eV2zE7