Looking at video cards and I see this picture here (http://www.newegg.com/Product/Showimage.asp?Mode=&Type=&Image=14-150-091-01.jpg%2C14-150-091-02.jpg%2C14-150-091-03.jpg%2C14-150-091-04.jpg%2C14-150-091-05.jpg&CurImage=14-150-091-03.jpg&Description=XFX+PVT45GUDF3+Geforce+6800GT+256MB+GD DR3+PCI+Express+x16+Video+Card+-+Retail). What's the metal bar on the top of the card (bottom of picture) for? I know I've seen it on other cards, too... but I have no clue if it serves any purpose. I was hoping someone here could shed some light on the matter.

I would have to guess
It is to help seat the card. ( usie it when pressing the card into place)

Keep people from pushing down on the heat sink ( breaking it off ) and protect the PCB

It can also be used for holding the card in place, for those with a case that has expansion card holders. But the bar needs to be taken off for use with SLI (it covers the SLI connector).

It would also give structural rigidity to the card [you can't bend the card even slightly].
A bit like a structural "I" beam that has flanges at top and bottom to confer rigidity in the horizontal plane.

Makes sense... thanks for the help!