I've logged this with scan tech support, but I might as well ask here too.
I bought a GA-K8NXP-SLI board and 2 GF6800GTs this week. Hooked them all up, everything appears to work fine, unless I try to enable SLI. Then the machine hangs as soon as I try to use 3d or alter the driver settings. I've tried reseating everything, various versions of drivers (66.93, 67.03, 67.66, 71.20), rebooting countless times, swapping the cards over, different monitors (analogue and digital). Nothing helps.
I'm fairly sure they have enough power, I have a Tagan 480W PSU and the molex->pci-e connectors are running off separate dedicated wires from the PSU.
So, can anyone suggest anything, or have I just got some duff hardware here?