The long or the short answer from an Architect?
The Short answer is above. You'll get more responsive on screen time. Rendering , won't do squat.
You could have the most powerful quad core CPU and the newest 8800 GPU and still won't help you.
Look here for the list of recomended cards where the GPU will do some of the render crunching:
http://usa.autodesk.com/adsk/servlet...linkID=9240618
Looks like your Quadro is there.
Any other card will work great for on screen work, but only those cards work to render becuase they are all hardware based solutions that don't pass the buck by doing software emulation for
anything. Most cards do not have full hardware compression and decompression. Not even most hard core gamers play games that can take advantage of it.
We run all machines at 4GB of DDR2 in the office and we still freeze up and have to walk away for a cup of coffee sometimes. Not that it is a bad thing.