ok, the reason y a GPU can draw more polygons is because it is optimized 4 doing that...a GPU is meant just for rendering all the graphics/drawing polygons/etc and nothing else...the following links should help:
http://www.webopedia.com/TERM/G/GPU.html
http://encyclopedia.laborlawtalk.com...rocessing_unit
http://en.wikipedia.org/wiki/Cpu
http://en.wikipedia.org/wiki/Graphics_processing_unit