Hi Scott,
I have possed the same question with little or no success at a straight answer. I would think that as long as the card you purchased meet the specs of the card Cisco has listed then you should be fine. By saying that I mean you could find a "Gaming" video card that could meet the "Workstation" card requirements.
If anyone else could share the cards they have tested that would be great! I am using a Dell Precision M4500, i7, 6G RAM, Nvidia Quadro FX 1800M, Windows 7 Enteprise. It can pass the Profiler tool for everything.
We are getting approval to build out a few workstaions for testing. I'll post here once I get them built and tested.
Cheers,
Ed