I'm not sure what to advise here. Hopefully there is someone in the community that has experience with one of these cards that can give you some advice. My advice is to buy from someone with a return policy so that if the card doesn't live up to expectations you can return it. Any of the approved cards for AE will work just fine in Premiere. The difference in rendering speed between cards in the same price range may be negligible.
Same as I wrote a hundred times elsewhere: If you expect miracles from the GPU raytracer, then you can just as well wait for NASA's Mars mission - won't happen. Any performance gains will be minor unless you have the money to buy multiple Tesla cards or whatever and your own nuclear power plant to provide them with enough juice. for everything else any of the cards will do just fine. No need to turn this into an academic exercise and make a scientific study on it.
I just got a GTX 580 for my system, thinking it would help the dog slow CS6 to perform at least as good as CS5.5.
Well, that didn't happen. I have a Quad Core Windows 7 system with 8 Gb ram. It was slow but useable on CS5.5, but is a disaster with CS6.
I think what it boils down to is the mother board and the memory isn't sufficient. I guess its time to go out and get that ivy bridge PC and 16 GB of ram. Because this just isn't going to fly.
Bottom line: beware before you throw out your CS5.5 discs or end your lease and go with CS6. You may be sorry. Like me. I subscribed to the Adobe Cloud, and CS5.5 isn't even available on the cloud.
If you expect miracles from the GPU raytracer, then you can just as well wait for NASA's Mars mission - won't happen.
I advise modifying that to read "MANNED Mars Mission". The newest Mars rover, Curiosity, is scheduled to land very late on Sunday, August 5.
Actually, it would be 6:31 AM on Monday in central Europe.
You have to make sure that you have the latest drivers are installed and that AE sees your GPU. Check the preferences and check the NVIDIA site for updates. The 580 should work very well for AE and extremely well for PPro.