What exactly determines whether video card will work with mobo?

this is a repost (sorry, mistakenly had the typo word report, my typing has gone south since I turned 45) of http://answers.yahoo.com/question/index?qid=20121228175627AAguuUZ
and I just wanted to get more/better/more accurate answers if there are any. is what was said accurate, or is there more to this?

people on toms hardware forum seem to say there is, but some folks on yahoo answers seem to think it's simply a matter of the slot you have the card plugged into. I used to think so too, but now I am not so sure.
like here: http://www.tomshardware.com/forum/322505-30-will-newer-video-card-work-semi-motherboard

just what sort of interaction takes place between the video card and the CPU that is or isn't simply handled by software?

I am curious if this is this a hardware flooding or starvation issue if you get the wrong video card or is it a software issue of the same. or both?

I am sure the whole determination process isn't magic. it is just an art form? is it learning by experimentation only?

I was planning on a new build:
i7-3970x
PNY (NVidia) quadro 4000 for use with Adobe, mediacoder, anything else in the future that happens to use CUDA (if audio editing with Cakewalk Sonar uses that).
mobo is asus p9x79 deluxe (socket 2011)
haven't picked out the 850W PSU yet. maybe I can again choose the pc power & cooling turbo-cool 860.
2-4 hd's
1 ssd
8x8GB DDR3-1600
3 blu-ray burners (I am a software developer and make my own discs and I also plan on authoring blu-ray discs)

the quadro 4000 is a workstation video card. I am hoping it will work fine in this configuration. or do I need a different kind of mobo/proc combination to do this?
http://www.nvidia.com/object/product-quadro-4000-us.html
http://www3.pny.com/NVIDIA-Quadro-4000-P2903C365.aspx
http://www.asus.com/Motherboards/Intel_Socket_2011/P9X79_DELUXE/
http://ark.intel.com/products/70845/Intel-Core-i7-3970X-Processor-Extreme-Edition-15M-Cache-3_50-GHz