Actually Quad crossfire means you can use 4 graphic cards of the same generation(AMD) and get the benefit of scaling of the Graphic capabilities, and simple crossfire means using 2 of the same generation(again AMD) in tandem to get a scaled up performance of you graphic capabilities, unlike mentioned by "imomum" with due respect this board can only be used for a masimum of 2 Graphic cards in crossfire as the board has only two PCI-E X 16 2.0 ports, and the other two are PCI-E X 1 so there is no way a modern Graphic card can fit or be used in Quad Crossfire, if you want Quad Crossfire you should go for Premium boards like maybe 990 FX that has 3 or 4(usually 4) PCI-E X 16 2.0 ports, hope that answers your question.