I've had this issue for a long time and moved to a laptop so I forgot about it. However I find myself wanting to use my old MacPro and this problem has resurfaced. I bought the 4870 512MB card from Apple and installed. Display looks great, internet is great, even playing back video at times is great...however in FCP7 and FCPX is where the real problems occur. I get this graphic snow in the playback of my footage. It covers the viewer and displays in colors of purple, green, white, etc. It's irritating and I know this card works with my 1st gen MacPro. Is there a way to update the card somehow? Maybe new firmware? I'm not very experienced with the hardware end of Macs or where to look for this kind of thing. Any help?