I got the 5770 because it was the only card I could buy that had a chance of working on my Mac. I was worried about my old ATI Radeon X1900 XT dying and leaving me with a dead machine. I read somewhere that my setup will only work with the DVI output, which is what I use.
I didn’t notice any difference with the new card in Final Cut, Compressor, or Photoshop–no problems, but no faster. I rarely do stuff that would require a lot of rendering.
Here’s some tests with the ATI cards in first generation Mac Pros: https://barefeats.com/wst10g5.html
It does bother me that within 3 years after buying this expensive workstation, it was unsupported by the manufacturer as far as replacing the graphics card.
Patrick Blackard
Texas-based shooter/gaffer, very part-time editor