Laptop faster than P4 desktop?

I just left a Cinema 4D render on overnight. It’s a 300-frame animation of a room with the camera doing a simple spinaround. I put 150 frames rendering on my P4-2.8GHz with 512RAM, and 150 frames rendering on my Centrino 1.6GHz with 256RAM. I checked it this morning, and the laptop had finished after 6.5 hours, but the P4 was still going (12.5 hours and counting. Should be done in another hour).

How is this so?? Is it a big difference in the CPU architecture or something:h:
Oh. and the 3D scene is pretty-much consistent throughout, so there’s no way one computer could have had a ‘harder’ section to render.