The review on xlr8yourmac listed the items in their box and it DID include the Crossfire Bridge and a Mac Pro 6-pin power connector. So I would assume it IS included in the retail box too.
It will but only with 8x PCIe. The 2006 dual core cannot be set up to have two x16 PCIe slots whereas the newer Mac Pro can. Running a single 3870 on an 8x slot instead of a 16x slot results in a loss in performance of about 7%. Running two 3870s in crossfire results in a 7% as well, not 14% as you might expect.
Barefeats say on their website that you'd be a loon for running crossfire at 8x, however, Toms Hardware report that yes, it does result in a drop in performance over crossfire at 16x but its not that bad a drop and its still way faster than a single 3870. Dual 3870s in crossfire are the fastest Windows graphics solution available using official supported OS X hardware in any Mac Pro right now.
I read a article on a review site "forgot which one" which showed the FPS count nearly doubling when 2 x 2600 xt cards were ran in the 2008 Mac Pro, I do not recall a bridge being used, just the two cards being plugged into the 2 x 16 pcie slots.
I read a article on a review site "forgot which one" which showed the FPS count nearly doubling when 2 x 2600 xt cards were ran in the 2008 Mac Pro, I do not recall a bridge being used, just the two cards being plugged into the 2 x 16 pcie slots.