I'm building a box primarily for work, but thinking about buying a good 16x video card for some gaming on it too. If I add a second card down the road for work does it also need to be a 16x card, or can I add a card in a slower PCI slot to run additional monitors? Any downside to this? (The work itself is not graphics intensive...trading and spreadsheets) If that's OK, then I can buy a MB with one 16x slot instead of a crossfire board and save some money. Thanks.