I wonder if the manufacture makes their own graphics engine in hardware and then has some sort of hardware interface that DirectX or OpenGL accesses. Maybe that is the acceleration part of a card. Creating a hardware function that replaces something that software would usually do is common.
That's basically it. OpenGL and DirectX are both essentially higher-level graphics languages. The general idea is that the drivers take that language and feed it into code that can execute on the CPU and GPU to create the actual frame. The more the drivers can offload to the GPU, the less the CPU has to do, and generally, the better the performance. (Now, that's an incredibly high-level view, and could probably be nitpicked to death by implementation issues, but it's sufficient for a general idea...)
The Quadro/FireGL cards have drivers that are designed to be tightly integrated into CAD applications, therefore they show better performance on those types of benchmarks, and worse performance on gaming benchmarks.
Unless you need a CAD workstation, having a Quadro or FireGL is not much help, and may even be a rather expensive hindrance in your system, compared to their GeForce/Radeon counterparts.
