Nvidia Quadro vs various dual output gaming cards

[fodog]

What are the main differences between a Nvidia Quadro type card (like NVIDIA Quadro FX 370 Video Card - 256MB GDDR2-$109) and the various dual output gaming cards out there (for instance the XFX GeForce 8600 GT XXX Video Card 256MB DDR3-$89)? I am contemplating building a new system for stock trading. Nvidia Quadro are used in workstations I know of but gaming cards seem faster and cheaper for same price-I must be missing something? Can you split the outputs of the Nvidia Quadros (ie get 4monitors hooked up to one dual output card with 4 independent windows of streaming data 1each on each monitor?) Thanks in advance...