When I get an SLI based system in the next few years when I finally get another job I'm going to have a gaming card in one slot, and a rendering card in another slot, and just switch between them.
And yeah, the 1900XTX would definietly beat the rendering cards any day, and even many cards below it, since they aren't programmed as well to support Direct X, since rendering tends to throw more towards Open GL based rendering, which if yo dont get this type of card, is done ALL in the processor with no help from the graphics card at all, except to display it.
So, saying that the new Quadro's etc wouldn't play games, also means, the 1900xtx, etc wouldn't do rendering