Major difference was his condition from the rear.
i must say he does look far improved from 04 to 06. i like his color more in 04 it seems a more natural stage color whereas in 06 if you cropped his face out you would think he was a black man. but he looks very good from the rear especially in that rear lat spread. i think his worst shot is his side chest. no vascularity or really pronounced leg seperation and just not very impressive. everything else looks pretty good though.
In 2006 pics his back seems less wide than 2004 because his lower lats and spinal erectors improved a lot. In my opinion 2006 was his best shape ever. I cant see the 2001 Jay winning the 2006 Mr. Olympia because Ronnie was a 296 pounds monster and guys like Dexter Jackson and Victor Martinez have high lats and small joints (they look bigger than they really are). But if the 2006 monster Jay had competed in 2001, he would have been the champion
Out of the night that covers me,
Black as the Pit from pole to pole,
I thank whatever gods may be
For my unconquerable soul.
In the fell clutch of circumstance
I have not winced nor cried aloud.
Under the bludgeonings of chance
My head is bloody, but unbowed.
It matters not how strait the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.