[quote]If I'm not mistaken you can only use 2 displays when using SLI (i.e only the main card's outputs).
Actually, if you don't have Windows 7 you can only use a single output of the four available when SLI is disabled. Windows 7 finally gives the ability to drive dual monitors in SLI mode.
In any case the outputs of a second GPU are disabled when SLI is in use.
Eh, that was a feature they added into the drivers, not the OS. If I remember correctly 185.xx onwards supported dual monitors with SLI, regardless of the OS. I used to be running 178.xx though so back then it was only one monitor for me and the remaining two on a PCI video card..