Okay,
Once again:
professional cards are made for quality.
Gaming cards are made for speed.
The FX is a gaming chipset... thus it has fancy drivers and a couple extra traces on the PCB.
It will perform close to a 5800 because all that is truly different is the driver. You can convert a 5800 to a quaddro with relative ease. Thus it is not that great for professional applications.
For that, a 3Dlabs card is great. Measuring in at a whopping ~750 3Dmarks (2001se) they provide the best quality of any card around, and absolutely suck for gaming.
The quaddro is a glorified gaming card, not worth the money.