If for example you have 2 X1900XT's (Master+Slave) - Do both of these mobo's let the Graphic cards run as Crossfire? I'm abit puzzled because both are SLi right? is it just a case of both using a different chipset on the mobo? confused. . .
Asus A8N-SLi Premium nForce4 SLi (Socket 939) PCI-Express Motherboard (MB-111-AS)
Asus A8R-MVP Crossfire (Socket 939) PCI-Express Motherboard (MB-129-AS)

Asus A8N-SLi Premium nForce4 SLi (Socket 939) PCI-Express Motherboard (MB-111-AS)
Asus A8R-MVP Crossfire (Socket 939) PCI-Express Motherboard (MB-129-AS)