The NVIDIA gamer series of graphics cards are targeted more towards the gaming trend, where the Quadro series are targeted toward the high end / graphics / CAD users.
Essentially what this means in english is the following: The gamer series of cards feature overclocking, rapid response memory optimization, and customizability. While these are all good, they are not targetting the high end CAD / Graphic Design / Video, etc. etc. users. I have noticed that on several of the current releases for the gamer video drivers, i have seen various stability issues with ArchiCAD (nothing major, but minor delays in redraws after zoom, or having to manually rebuild plotmaker files). These symptoms stem from the fact that the drivers of the gamer series are optimized for rapid, on the fly computations, which are run on the chipset, then cleared, and a new one is run, so on and so forth. These cards aren't specifically built for a steady run of computations that video editing, and CAD would require from them. In a nutshell, the Quadro is targeted at users that don't need all the high level processes that you'd need for the latest and greatest game. The Quadro series of drivers are meticulously optimized with a variety of high end computing applications in mind.
Now. . .that being said, I haven't personally seen or run any benchmarks, or compatibility tests with the Quadro cards on ArchiCAD, but, I don't see why you shouldn't be happy with the Quadro card.
