What is the best video card for early 2008 Mac Pro 8 core?

If there is RAM that is not showing in the Memory pane of System profiler, that means your RAM DIMMs have failed.

If your screen is dark, your graphics card may have failed, but its RAM is never show directly -- it is hidden in the details of the Graphics & Displays pane.

What does that have to do with picking the best video card?

ram not showing in system profiler

Best video card

ipso facto: mac has bipolar or split personality disorder :-(