Maximum PC

I have the Gigabyte GA-Z77-DS3H motherboard which has 2 PCI Express x16 slots. Can I run a different cards in each slot (for example, a ATI HD6870 in one slot for game playing and video playback, and an Nvidia Quadro in the other slot for CAD/Video editing. Unfortunately, from what I've found, CAD cards aren't as fast as gaming cards, and some gaming cards aren't really good for CAD. That's my problem.
Unfortunately, the software that i use for CAD/video work only really works on certain certified hardware (in order for me to get any support from them I have to be using a certified or tested video card, and the 6870 isn't on their list since it's primarily a gaming graphics card and not a CAD card--so I think I may need to get a Quadro for work--video and CAD, and a gaming card for games and everything else).

Any suggestions on doing this (if it can be done)? I know the board will support CrossfireX with the same two cards, but can you run two different cards independently (not at the same time, but allow you to change back and forth from Windows 7).

While I believe Windows is just fine with two video cards, your programs may freak out over which one to use... though I think they default to whatever is in the first PCI-Express x16 slot.

Workstation cards aren't exactly gaming performance anemic, but I don't think NVIDIA released anything based off Kepler recently.