Hi ,we are making 2 (unofficial) tests with rendering time with both version in those topics .It's a fact that Marcel who owns a bi_xeon is rendering 2 time faster than anyone else
HERE you can test your config :
BASIC Scene
and Here
The 2,1Millions poly scene
what you have to do is to download the attached file of each first message .Just open as it is and render as it is without tuning any settings by yourself