Kelavarus
Yes. Actually, it is basically 80% the driver what makes for the price difference (increased memory size adds too and some components) and why many gamers are tempted to load the Pro driver into a gaming card. But yes there are 2 or more separate drivers optimized for very different functions. Pro drivers are optimized for reliability and stability but also are produced to support specific Pro applications features and even some drivers versions are specific for one application. Is in this high optimization process where Nvidia has become more consistent, supports more specific apps and a broader set of functions. But one point with this article is to indicate that you can't count ATI-AMD out of the Pro industry as there are specific scenarios or production pipelines where the integration offered by the same CPU-GPU manufacturer is key.
Pro GPUs are build using better components, where is possible, to produce a longer life and reliability. They usually include more on board memory and are "underclocked" compared to gaming counterparts. The lower clock frequencies helps the hardware to run cooler and more stable. And Pro graphic cards comes with fast exchange warranty programs if the card fails. Also they have support, that you will never have if your gaming card fails any time in the production or development process.
If your job doesn't depend on high reliability or stability it will be hard for you or for a small studio to pay $3000 or more for the top Pro graphic card, plus premium price for workstation parts, but in a big production studio it will be a dumb decision to "play" with the system components you depend on 24-7 to "save" money, when what you really need is the system up and running.
I can't confirm this, but I read you can't load Pro drivers anymore into the latest Nvidia cards as there are included circuity to prevent this. I don't know if AMD-ATI has done something similar.
I have an entry level Pro Nvidia card, a Quadro 580 ($170), and I am extremely happy with it. It consumes 40 watts at full performance and gives me top support in Maya modeling, Zbrush and Photoshop. So I wont expend $400-500 in a top gaming card with loaded drivers. Nevertheless, if I need top Pro performance on a low budget I may try the "cheap" way. I am not judging anyone.