If im mining with 2 ati cards, do I put on the crossfire bridge between the two cards, and do I enable crossfire? Or just run the two cards as separate workers?
6 million posts already talking about this, but I'll answer it anyway and kindly request that you use the search function next time.
If you use Linux you don't need to Crossfire and the OS will see and use both cards.
If you use Windows you don't need to use Crossfire, but Windows won't see the second card unless it thinks there is a monitor on it. This can be spoofed using a VGA dummy plug. http://www.geeks3d.com/20091230/vga-hack-how-to-make-a-vga-dummy-plug/
I have 3 ATI cards all running on Windows without Crossfire.