this isnt off topic, this is trying to identify your needs so that we can recommend you a good one. You haven't even given any details as to what this sound card should need (7.1, etc). I would assume you are looking for something that the stock soundcard doesn't provide? All you have stated is that it needs to be PCI-e 2.0.
With all due respect, this is off topic. How can you "recommend you a good one" if there are none? I am not asking for advice on how to process my audio tasks. Instead I am asking for the identity of operational sound cards. If you actually know of any working sound cards please list them.
The reason I am being somewhat short with you is that I have read about 50 other threads on other boards on my original topic (what cards will work?) and people always come in and suggest that external solutions (usb/firewire etc.) can work and the internal Mac Pro card is ok too. True but this always derails the thread from the orginal topic which is "what internal cards are compatible?" and there is never even a single suggestion as to a working sound card. I want to avoid this discussion here and have people list compatible internal sound cards if they know of any.
I do know of the RME card, so thank you for the link. This is the about $1000 card I mentioned in my first post and the only one I was able to confirm that can work with the newer mac pros. Link-
RME Card about $1000
So if anyone knows of any internal sound card of any type that will work, in addition to the RME Card, please let us know. There may be an Apogee card but this would also be about $1000 or even much higher, and this is beyond my price criteria. So other than these $1000 pro cards I still say tha there are no compatible cards. I may be wrong, but I don't think so.