Here's a link to a comparative review of desktop Quadro (including Quadro FX1400) and 7800GTX cards in SpecViewPerf 8.1 benchmarks....http://features.cgsociety.org/story_...id=3321&page=3
The 7800GTX (even in SLI mode) gets soundly trounced by the FX1400 in all of the results, with the FX1400's performance gain being anywhere between 20% (in the EnSight Viewset) up to almost 200% (in the Pro/Engineer Viewset).
However, the FX1400's gain in 3DSMax is only 66% and in Cinema 4D benchmarks it's actually slower! Also, these benchmarks are only synthetic and cover a wide range of functions whereas your needs may be more specific to a particular regular function within a particular application.
Not to mention that the benefits of a professional 3D card are seen only in Pre-vis as an aid to workflow and you may find the performance and accuracy of a GeForce card is more than adequate for your needs (as I do).