I had the same concerns for upgrading from PPCS5 to CS6 because my video card isn't even listed on the specifications list. I downloaded the trial for CS6 and was surprised it worked. The only thing is I had to update the trial software because I had issues prior to that. Before the update, the play button wouldn't work and it wasn't reading my fonts correctly. I am hoping to upgrade soon when they get the store fixed.
I would do the trial before sinking money into a new graphics card. It might help, but may not be necessary. Sorry I can't help you with which is the right graphics card.
CS4 does not really use any advanced features of any card... so a relatively inexpensive AMD/ATI card will do anything a more expensive card will do... for CS4
Starting with CS5 (a complete rewrite of the source code, to go from 32bit to 64bit, plus a LOT of other changes) an nVidia card helps with some actions
For a list of supported nVidia CUDA cards go to the CUDA help page - http://forums.adobe.com/thread/773101
For many others, with at least 1Gig of video ram, use the nVidia Hack http://forums.adobe.com/thread/629557 - which is a simple entry in a "supported cards" file
Which nVidia card you buy will be a combination of 2 factors... how much $$ you want to spend for a given speed level (number of Cuda cores) and the size of your power supply to drive the card
For a PARTIAL comparison of nVidia cards http://www.pacifier.com/~jtsmith/GPU.HTM
Thank You for your input. I have looked into the cards that you have info about and I know that the lesser cards can be used but I am trying to take advantage of the higher end cards cuda cores as you spoke of as well as have the best update
and upgrade for the buck. On the system currently running the Quadro 2000 card it has a 800watt power supply. The other system running the GTX 285 carrd has a 460 watt power supply which I was planning to upgrade anyway soon.
I waited on hold an hour and a half with Adobe Tech support but found out that they don't know anything anymore about video cards. I was amazed because when they were located in the US they were very knowledgable. So basically we're
on our own to make hopefully the correct decision! I just don't want to have to rerender PPCS4 one hour programs from the past just to utilize them again through PPCS6. I hope someone with a recent similar problem can speak to this.
[moved to hardware forum]