I noticed that professional video cards like nvidias quadro fx cost a lot more than even the newest GeForce 8 series cards, and was wondering what the difference is between video cards used for prerendered graphics and real-time rendering cards like the new GeForce 8 series? I mean, if I bought an nvidia quadro fx, would I be able to use it to play games, or just for 3d animation?
The Quadros and the ATI FireGLs are pro level OpenGL accelerators that basically accelerate OpenGL functions through GL drivers.
Normal PC "game" video cards like ATI X1 and X2 and GeForce 7 / 8 series accelerate mainly polygons, transform (rotation and such), lighting, and shading. That's actually VERY LITTLE of OpenGL's capabilities. (You ever tried looking through the OpenGL standard's book?) Remember, games want to boast max amount of triangles, texture elements (texels), and so on per second, where as the Pro cards actually measure performance by some other ways.
So basically we're comparing apples and oranges. Think of our GeForce 8 as... say, a Top Fuel Dragster. And the Quadros as... A Champ Car or a Formula 1 car, a different type of machine altogether. Both are extremely fast... within their design environments. 
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