Yes a NVIDIA card will work on a crossfire board.PCI-E X16 slots are all the same.The difference lies in the chipset.If you have a CROSSFIRE board,you can run either a NVIDIA card or an ATI card.If you want to run crossfire on that board though,bothe cards must be ATI.The same goes for SLI boards.They'll run either manufacturers single cards,but to run SLI you need two NVIDIA cards.Hope that answers your question.Goodluck.
Dahak
M2N32-SLI DELUXE WE
X2 5600+ STOCK (2.8GHZ)
2X1GIG DDR2 800 IN DC MODE
TOUGHPOWER 850WATT PSU
EVGA 8800GT SUPERCLOCKED
SMILIDON RAIDMAX GAMING CASE
ACER 22IN WS LCD 1680X1050
250GIG HD/320GIG HD
G5 GAMING MOUSE
LOGITECH Z-5500 5.1 SURROUND SYSTEM
500WATS CONTINUOUS,1000 PEAK
WIN XP MCE SP2
3DMARK05 15,686
3DMARK06 10,588